100 Above TDZE Prior to MAP on LOC/DME???

[FN FAL]

FN FAL,
not sure I'm reading your post correctly. You're using Radalt for setting mins for non-precisions? I just know how we do it in the reserves and at my airline, and we set MDAs in the Baro for most stuff. At my airline, the only time we set the MDA in the radalt is CAT II ILS and below.
It seems that setting a non-prec min in the radalt is not ideal, since it is a height above airport, versus a precision height above TDZE. Especially since you'll get weird indications like the trees and ridges and whatnot. Seems that setting MDA in Baro, and scanning the Radalt for SA would be a better choice.
thoughts?

Yes, I set it for non-precisions. You do get more alarms than you'd like, but it is the only terrain avoidance warning I have. Worst case scenario is that it goes off and makes you look at your altimeters.

I think if you read the original poster's posts, he makes mention of radar altimeters. I don't think GPWS would do any better...I hear of guys saying they go off all the time during approaches.

It's a tool...it's not what I use to actually fly the MDA. In single pilot IFR flying, you sure don't want to set up a 1,000/1,500 FPM descent after the FAF and forget to level off at MDA. The radar alt is just used as a safety catch...it's a tool and I use all the tools. One tool we don't have have is GPWS, nor do we have altitude preselect on our autopilots. We do have an altitude alarm on our KLN-89B GPS, which I also use most of the time, but you have to round up the altitudes to the nearest 100 feet, because you can't enter a number like 376 in it. You'd have to enter 400.

Our company manual states that we are to set the thing to the highest setting for departure and cruise...just in case you wind up snoozing or losing positional awareness. It could just save your bacon if you need it. If you leave it at 200 feet after the last ILS, you would only have 200 feet of warning if there was an 'anomaly' during the flight.

 

[firstthird]

Since I've done very little single pilot IFR, I'll defer to your judgement. I have a lot of respect for you guys that do that. I'm definitely spoiled after flying multi-pilot for so many years. (edited for clarity)

 

[FN FAL]

As a post script, one of the airports that I shoot the most ILS's into, which has the worst weather when it's bad out, is on a hill. The radar altimeter doesn't show a very good profile until you are right at mins...the rising terrain there is a b!

 

[Xav8tor]

I'm still working on finding a public host for images, charts, and pdf's and other docs that will help everyone understand the issue and participate. This got a little bigger than I thought it would but I'd like to see us come up with a solution to suggest needed changes and actions to prevent another one like this from happening. Meanwhile, I do have an excerpt of the CVR that will fit (I hope) as a single message. Maybe that will help some of you too in your analysis and thinking about the problem. It did give me a better picture of the thought process. These things are hard to read if you do it right (nothing like listening to one though), but don't let your emotions take over.

I'm not a mod or forum cop, but PLEASE don't let this thread go OT and freak out over what you read, or the fact that it is even a public document. Use it to put yourself in the same situation and integrate it with everything else you know that is relevant and reliable. Remember the questions before us: 1) Is the ALS a green light to leave MDA more than 1/2 mile out on a LOC? and 2) would seeing that +/- 1059 foot obstacle on the NACO plate have changed your mind, even though you thought you were OK under 91.175 going to 1064' with (just) the approach lights in sight?

For further discussion, remember the 32 did not have VNAV and a VDP was not charted. We know VNAV/VDP is a possible alternative, but there are problems making your own there too (as noted above). Also, when a VDP isn't charted on the plate, that means there's an obstruction that prevents using one (or at least the FAA from depicting one). Think about that for a sec. On the IRK 36 LOC/DME the controlling obstacle is trees at approx 100' agl about 3/4 to 1 1/4 nm out and on the centerline. Only the highest point is on the govt. plate, nothing on the Jepp, but a topo depicts a row or "clump" of trees along the path. A sat photo makes it clear that 100 agl 1 mile out is not a good idea.

Any other suggestions for a public place to post the whole docket (pdf's and jpeg's)?

OK, here comes that last few minutes of the CVR from where they were cleared to the end.

 

[Xav8tor]

CVR Transcript of 5966 beginning at approach clearance. I did edit out a few words at 1931:01 to :11. The NTSB group normally would have deleted them too as irrelevant and/or profanity, but it appears nobody in the group knew what the words meant so they left them in. It was really strange, they didn't even spell it correctly. Otherwise this is what was on the tape that they put in the transcript. There are probably other transcription errors and they definetely do leave certain other sounds out without any indication that it was done.

_______________________

1930:30
CTR2 CorpEx fifty nine sixty six uh, one one miles south of uh,
KEMMY. turn right heading three, three zero. maintain three
thousand until established on the localizer. cleared localizer
DME runway three six approach at Kirksville.
1930:41
RDO-2 three thousand feet 'til established uh, heading three three zero.
cleared for the localizer DME runway three six into Kirksville CorpEx
fifty nine sixty six.
1930:50
HOT-2 thirty three, three thousand ‘til established. cleared for the approach.
1930:54
HOT-1 cleared the approach.
1931:00
HOT-2 cleared for the approach.
1931:01
HOT-1 ###### the approach. you're ########. approach #########.
[sound of chuckle]
1931:11
HOT-2 [sound of chuckle] ** [######### ### #####] that's funny when it
happens too. [######### ### #####] is that a ##### yeah. [sound
of laughter] he ########. thirty one.
1931:27
HOT-1 thirty *.
1931:30
HOT-1 [humming sound] thank you.
1931:34
HOT-2 course alive. cross check, no flags except for the vertical.
1931:41
HOT-1 the wertical. get up there ##. keep it slow. all the time we need.
[sound of humming]
1932:06
HOT-1 let's go flaps ten and we'll configure early too.
1932:11
HOT-2 all right. flaps ten....
1932:12
HOT-1 give ourselves as much time as we can.
1932:13
HOT-2 selected indicating ten.... since we're not going to doing holds
like that one #.
1932:22
HOT-1 right.
1932:24
HOT-2 **.
1932:30
HOT-1 and it, was it five point?
1932:31
HOT-2 five point two.
1932:32
HOT-1 five point two.
1932:33
HOT-2 I'll call it out for you.
1932:35
HOT-1 okay. we can go to what, twenty five right now?
1932:37
HOT-2 twenty five right now.
1932:38
HOT-1 okay, gear down, flaps twenty, before landing check.
1932:45
HOT-2 [sound of a sigh] all right.
1932:46
HOT-2 dow, gear down, three green.
1932:48
HOT-1 three green.
1932:49
HOT-2 uh, prop syncs are off, speeds are high. flaps selected indicating
twenty. hydraulic brake pressure normal. standing by the flows.
1933:07
HOT-1 [sound of humming]
1933:17
HOT-2 twenty five.
1933:41
CTR2 CorpEx fifty nine sixty six, frequency change approved. report
the down time on this frequency or through flight service.
1933:46
RDO-2 all right, frequency change approved. we'll cancel with you on
the ground, CorpEx fifty nine sixty six. so long.
1933:51
CTR2 roger.
1933:52
HOT-B [sound similar to frequency change alert]
1933:55
HOT-1 make sure those lights are up please.
1933:56
HOT-2 all right.
1933:57
HOT-1 thanks.
1933:57
RDO-2 [sound similar to seven microphone clicks]
1934:04
HOT-2 seven times I clicked it. I ####### it.
1934:08
HOT-1 what we can do is, well is call Kirksville ops and ask them to confirm
that they're up.
1934:13
HOT-2 all right.
1934:13
HOT-1 that would be kinda nice.
33 of 37
1934:14
RDO-2 Kirksville ops, CorpEx fifty nine sixty six.
1934:22
HOT-2 aw speeds.
1934:21
KOPS fifty nine sixty six.
1934:23
RDO-2 yeah, can you tell me if uh, the approach lights are up?
1934:37
KOPS lights are on.
1934:39
RDO-2 cool, thanks.
1934:51
HOT-1 come on you ##.
1934:52
HOT-2 # it. pig, isn't it?
1934:55
HOT-1 sure is.
1935:06
HOT-1 what happened to our identifier?
1935:09
HOT-B [sound of Morse code identifier] R-K.
1935:10
HOT-1 I don't have it any more. do you? localizer?
1935:16
HOT-B [sound of Morse code identifier] I-I-R-K.
1935:19
HOT-2 I got it.
1935:20
HOT-1 okay.
1935:22
HOT-1 DME went off line.
1935:26
HOT-2 not on my side. five point seven.
1935:28
HOT-1 okay.
1935:29
HOT-2 five point six.
1935:30
HOT-1 okay, mine's back.
1935:31
HOT-2 five point five.
1935:38
HOT-1 I can hear it.
1935:39
HOT-2 there you go, KEMMY. down to thirteen twenty.
1935:42
HOT-1 thirteen twenty, here we go.
1936:02
HOT-1 when we get within a hundred feet if you'd uh, arm that uh....
1936:06
HOT-2 disarm it?
1936:06
HOT-1 ... director again yeah uh, altitude.
1936:08
HOT-2 oh for * [one member heard "altitude"], okay.
1936:18
HOT-1 c'mon, go down there.
1936:23
HOT-2 five hundred, four hundred feet to go.
1936:24
HOT-1 *.
1936:30.6
HOT-3 five hundred.
1936:33.9
HOT-2 thirteen twenty.
1936:35.7
HOT-1 what do you think?
1936:35.9
HOT-1 thank you.
1936:36.8
HOT-1 I can see ground there.
1936:37.2
HOT-3 minimums, minimums.
1936:41.9
HOT-2 I can't see #.
1936:43.5
HOT-1 yeah, oh there it is. approach lights in sight.
1936:44.2
HOT-3 two hundred.
1936:44.7
HOT-2 * in sight.
1936:46.6
HOT-2 continue.
1936:47.7
HOT-1 we get rid of the director.
1936:48.6
HOT-B [sound of beep]
1936:50.5
CAM [sound similar to increase in engine RPM]
1936:50.5
HOT-1 getting a little slow.
1936:50.6
HOT-2 flaps thirty five?
1936:51.9
HOT-1 no....
1936:52.2
HOT-3 sink rate.
1936:52.8
HOT-1 ...no.
1936:53.2
HOT-2 trees.
1936:54.0
HOT-B [sound similar to stall warning horn]
1936:54.4
HOT-1 no, stop.
1936:55.2
CAM [sound of impact]
1936:56.6
HOT-1 oh, my God.
1936:57.0
CAM [sounds of numerous impacts]
1936:57.5
HOT-2 holy #.
1936:58.6
END of TRANSCRIPT
END of RECORDING

 

[CatYaaak]

I'm not a mod or forum cop, but PLEASE don't let this thread go OT and freak out over what you read, or the fact that it is even a public document. Use it to put yourself in the same situation and integrate it with everything else you know that is relevant and reliable. Remember the questions before us: 1) Is the ALS a green light to leave MDA more than 1/2 mile out on a LOC? and 2) would seeing that +/- 1059 foot obstacle on the NACO plate have changed your mind, even though you thought you were OK under 91.175 going to 1064' with (just) the approach lights in sight?

For further discussion, remember the 32 did not have VNAV and a VDP was not charted. We know VNAV/VDP is a possible alternative, but there are problems making your own there too (as noted above). Also, when a VDP isn't charted on the plate, that means there's an obstruction that prevents using one (or at least the FAA from depicting one). Think about that for a sec. On the IRK 36 LOC/DME the controlling obstacle is trees at approx 100' agl about 3/4 to 1 1/4 nm out and on the centerline. Only the highest point is on the govt. plate, nothing on the Jepp, but a topo depicts a row or "clump" of trees along the path. A sat photo makes it clear that 100 agl 1 mile out is not a good idea.
.

To clarify the VDP's publication or it's absence. Your statement that it's absence "means an obstruction exists" isn't exactly correct. Under the current TERPS criteria, a VDP will be charted if there is DME available to the runway AND established at a point where a VGSI (VASI OR PAPI) slope intersects the MDA altitude. VSGIs angles are adjusted in slope with regards to close-in obstruction clearance. But you have to remember, that VSGIs also have a distance limitation regarding obstruction clearance even when in sight. Therefore, the lack of DME or a VSGI will also preclude charting a VDP, even if there isn't an obstacle.

The risk of interpreting it your way is if someone takes it inversely...that they assume because a VDP IS charted, that NO obstacles and or terrain comes into play and they wind up doing exactly the opposite from why they are published, and dropping down too early. A VDP's sole purpose is to give you a definable and safe "normal position to land" point at which to leave the MDA...but ONLY if you see the runway/lights, and following the VSGI if installed.

Frankly, I've never heard of applying the precision-approach rule that says you can descend below DA to 100' above TDZE using ALS cues to descend below MDA on a non-precision appch. Dropping to 100' above TDZE based those alone is a surefire way to eventually get someone killed, and I honestly can't believe that this is being done, let alone taught in-house somewhere. What kind of moron even goes as far as saying they'll maintain this 100' DeathWish altitude "until intercepting the VASI"?.....they've just admitted that there IS a VASI, ONE WHICH MAY EVEN BE ADJUSTED TO A HIGHER-THAN NORMAL SLOPE TO AVOID OBSTRUCTIONS OR TERRAIN (and they just drove in below it!).

This whole thing is only muddied if you wound around the axle forgetting the Prime Directive of any non-precision approach, which is....

MAINTAIN MDA UNTIL IN A NORMAL POSITION TO LAND!!!

The only way to determine that position is by visually maintaining a desired vertical path to the landing point, and by itself, AN ALS DOES NOT GIVE YOU THE INFORMATION IN ORDER TO DO THIS! That why they invented VSGIs and use higher visibility minimums on non-precision approaches in the first place. With no runway or runway lights, an ALS does not give you the visual cues needed to establish a proper glidepath, therefore a "normal position" from which to leave MDA..let alone adjust for terrain. It's a lateral cue.

There's another guaranteed, killer trap using that tecnique even if you don't become a smokin' hole prior to the runway....winding up as one during the Missed Approach. A charted MAP(rocedure) guarantees terrain/obstacle clearance ONLY WHEN BEGUN AT THE MAP(oint) AND AT THE MDA OR HIGHER. The charted lateral navigation is predicated on these TWO criteria.

So you're flying into a mountain airport where the MDA is 3000' above TDZE, and using only the ALS that's burning brightly (no runway in sight, no VASI in sight) you descend to (gulp) 100' above TDZE right away, completely blowing-off any attempt to estimate what would be a "normal" (meaning based on at LEAST 300' per nm, because at 10 miles out with no VASI it still might not be enough). Say you actually survive for awhile, but suddenly see terrain looming at about 1.5 miles from the airport..you're all dirtied-up, and slow. Say you're friggin' good though, and climb enough to miss it...you didn't see it earlier because either visiblity isn't good or it's a "virtual IMC" VFR night..now your gear is up, climbing, and lost sight of the ALS too. No good..not a "normal position". Or, what if no heroics required, but even though you used the ALS you don't see the actual runway (or lights) because of bad vis (snow flurry, ground fog, etc). So now what?

You fly the Missed Approach Procedure? Well, as critical as beginning the procedure at the MAP, is the REQUIREMENT that you do so AT THE MDA OR HIGHER. The "Drive it in at 100' and hope you see the runway" lunacy means that you're at your MAP almost 3000' lower than what the procedure is predicated on! In the mountains, that means "Game Over", and you're only saving grace is if there's an Obstacle DP based on T/O from that runway you can quickly revert to, and it's been briefed (which it should be for a high-MDA apt). However, some airports don't even have an IFR Obstacle DP from the Instrument Approach runway (Aspen and many others are like this). In that case, the MAP(rocedure) will only succeed in planting you smack into some cumulo-granite. If you can't get back up to MDA by the time you cross the MAP(point) so you have to be able see the surrounding terrain in order to maneuver if you can't make it back up to the MDA/MAP(oint) window.

This made-up technique is obviously the province of flat-lander pilots within one company making up stuff and getting away with to the point they don't see how dangerous it is. It will, and has numerous times, gotten people killed in less-forgiving places. Sounds like in-house they've developed a cocoon-atmosphere with some dangerous habits that need someone to come in and address, starting with TERPS and basic instrument procedures understanding. It sounds like the misundertanding runs scary-deep, so it'll probably happen.

 

[enigma]

Frankly, I've never heard of applying the precision-approach rule that says you can descend below DA to 100' above TDZE using ALS cues to descend below MDA on a non-precision appch. Dropping to 100' above TDZE based those alone is a surefire way to eventually get someone killed, and I honestly can't believe that this is being done, let alone taught in-house somewhere. What kind of moron even goes as far as saying they'll maintain this 100' DeathWish altitude "until intercepting the VASI"?.....they've just admitted that there IS a VASI, ONE WHICH MAY EVEN BE ADJUSTED TO A HIGHER-THAN NORMAL SLOPE TO AVOID OBSTRUCTIONS OR TERRAIN (and they just drove in below it!).

This whole thing is only muddied if you wound around the axle forgetting the Prime Directive of any non-precision approach, which is....

MAINTAIN MDA UNTIL IN A NORMAL POSITION TO LAND!!!

Darn Good Post.

ditto to the above quote,

enigma

 

[TurboS7]

That transcript is scary and all of us have been there, ho hum just another approach. They thought of everyting and really didn't miss much. Something went wrong right at the last but nothing was done about it. At that point max thrust, immediate go around and get out of there, then figure it all out would have been the prudent thing to do. Because we are all focused on the hotel van and pride ourselves getting the job done we loose sight off the big picture. Sometimes you need time to think, especially if you are tired. Get up and away from the terrain, then you can piece together what went wrong. Right along with that comes needed having enough fuel to get up and away. Pressure is on us all to carry as little fuel as possible, in reality we give away the only option we have to decompress our thinking. All these fancy approaches are nice but they also lend themselves to confusion if things don't start to work properly. Especially in a multi-pilot airplane and one crewmember is up on the procedure and the other isn't and starts trying to give input at the wrong time.

 

[DisrespectedJ32]

For those of you following this thread:

FYI.

HOT-3 from the last 30 second of the CVR is the Radar Altimeter Call outs and the GPWS.

J32

 

[Xav8tor]

Cat,

Thanks for the input ref whether a VDP is charted or not, and why/why not. I haven’t gone that deep into the TERPS yet on this VDP issue, but I retrieved that theory from the website of a guy who seems to be an somewhat of an IFR afficiiando (I think it was called Whitt’s Flying). I guess it is an oversimplification (at best). The explanations and references an FAA engineer in the NACO Flight Procedures Office gave me are going to take me some time to digest and research further. At the time I last spoke with them, we focused on the obstacle charting question and barely even touched on the VDP angle (pun intended).

Also, I am not sure yet exactly how the non-coincident descent/VGSI angles might come into play here as related to the controlling obstacle, VDP, etc., if at all. I haven't had time to draw all of it manually in PS. I have some really nifty flight reconstruction software but that won't do it and I don't have the approach procedure design equivalent program, or the thousands of bucks it costs to buy/lease it. Anyway Cat, your response is exactly the kind of well thought-out participation I hope to see more of. From the “prime directive” through the rest of your response, many thanks for reinforcing and further clarifying the dangers of this problem.

Can anyone point us towards the specific section of the TERPS or any other authoritative documents that cover the design criteria for charted VDP’s (or lack thereof) in a situation like that at IRK? I’ll do what I can too, but my wife says I need to spend less time on this board and more time painting/plumbing/weeding or pouring over FAR’s and accident reports for a fee, not fun or a sense of “duty.”

Also, for those of you that have contacted me via email and PM, I am in the process of rebuilding my lab/office, and in addition to transferring files/settings etc. to a new 600 series screamin' demon of a computer, new firewalls and network security etc, that will mean I am out of touch from here for periods of time, (which will probably make some people very happy). Please don't let this thread die until we come up with the right answers and a way to do something about it.

PS-Still looking for a free public host to post images, charts, docs, etc. to go along with this thread.

 

[Clutch_Cargo]

I'm with enigma... good post Cat!

Order 8260.3B, Chapter 2, Section 5, Paragraph 253 This link to VDP criteria is to Change 19 (the most recent) only to keep the download to a manageable size. Click here if you'd like the entire TERPS through Chg 18. These are both .pdf files.

I already gave my position 5 pages ago but I will add that most pilots probably did not receive much education on TERPS during their training and what they did get was probably taught in a roundabout way. Honestly, I can understand why... the directive is huge and filled with all kinds of analysis and design minutia. But sometimes you have to take the initiative to learn in this biz. Not knowing, not knowing how small the margins can be, can get you killed.

The requirements of 91.175(c) are pretty clear. Properly applied, they probably would have been enough to prevent this accident. It sounds as though some are forgetting that it takes all three requirements in order to operate below DH/MDA:

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and for operations conducted under part 121 or part 135 unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;
(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach being used; and
(3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified by the Administrator, at least one of the listed visual references for the intended runway is distinctly visible and identifiable to the pilot.

At face value, it would seem that this crew forgot number 1. I'm not judging... "There, but for the grace of God, go I." We've heard a number of good tips or tricks for helping judge when you meet that first requirement but first you have to know that you must meet it.

So, to answer your questions:

1) Is the ALS a green light to leave MDA more than 1/2 mile out on a LOC?

No, not necessarily.

2) would seeing that +/- 1059 foot obstacle on the NACO plate have changed your mind, even though you thought you were OK under 91.175 going to 1064' with (just) the approach lights in sight?

Well, obviously it wouldn't have changed my answer but I do think it would be good information to have. It might help drive home the point that the margins are small.

XAv8tor, I have a couple of questions for you, if I might. You have made mention of your work, in a roundabout way, several times in this thread; what exactly do you do? You have also mentioned that you are not fishing here but is your interest purely, for lack of a better word, Samaritan in nature? In other words, is this just a hobby or personal interest for you where you might be able to help others or are you connected to or involved in this or some other similar case? I only ask because I don't know you and this is the internet. I'd hate to think that something I've said might be used in some way to hang some poor, dumb bastard without my knowledge.

cc

 

[Clutch_Cargo]

Some food for thought from the AIM 5-4-5:

i. Pilot Operational Considerations When Flying Nonprecision Approaches. The missed approach point (MAP) on a nonprecision approach is not designed with any consideration to where the aircraft must begin descent to execute a safe landing. It is developed based on terrain, obstructions, NAVAID location and possibly air traffic considerations. Because the MAP may be located anywhere from well prior to the runway threshold to past the opposite end of the runway, the descent from the Minimum Descent Altitude (MDA) to the runway threshold cannot be determined based on the MAP location. Descent from MDA at the MAP when the MAP is located close to the threshold would require an excessively steep descent gradient to land in the normal touchdown zone. Any turn from the final approach course to the runway heading may also be a factor in when to begin the descent.

1. Pilots are cautioned that descent to a straight-in landing from the MDA at the MAP may be inadvisable or impossible, on a nonprecision approach, even if current weather conditions meet the published ceiling and visibility. Aircraft speed, height above the runway, descent rate, amount of turn and runway length are some of the factors which must be considered by the pilot to determine if a landing can be accomplished.


2. Visual descent points (VDPs) provide pilots with a reference for the optimal location to begin descent from the MDA, based on the designed vertical descent angle (VDA) for the approach procedure, assuming required visual references are available. Approaches without VDPs have not been assessed for terrain clearance below the MDA, and may not provide a clear vertical path to the runway at the normally expected descent angle. Therefore, pilots must be especially vigilant when descending below the MDA at locations without VDPs. This does not necessarily prevent flying the normal angle; it only means that obstacle clearance in the visual segment could be less and greater care should be exercised in looking for obstacles in the visual segment. Use of visual glide slope indicator (VGSI) systems can aid the pilot in determining if the aircraft is in a position to make the descent from the MDA. However, when the visibility is close to minimums, the VGSI may not be visible at the start descent point for a "normal" glide path, due to its location down the runway.

3. Accordingly, pilots are advised to carefully review approach procedures, prior to initiating the approach, to identify the optimum position(s), and any unacceptable positions, from which a descent to landing can be initiated (in accordance with 14 CFR Section 91.175(c)).

​

Something else that could or should lead a crew to think about what is underneath them is the note: "VGSI and descent angles not coincident." The optimum descent angle is 3.00 degrees and the AIM tells you that, when possible, the approach is designed to the optimum. TERPS will tell you the descent angle can be as great as 3.77 deg. Straight-in mins are not authorized for descent angles in excess of that. On the approach in question, the descent angle is 3.41 deg and not coincident with the 3.00 deg slope on the VASI. That should make you question why. What is out there? The 3.41 deg descent angle is advisory, you do not have to follow it, and as some have noted, they like to get to MDA early (chop and drop) so they have some time to look around. But you can still use it to get a rough idea of when you want to start down from the MDA... in this case, doing the math will tell you that 3.41 deg slope intercepts the MDA .9 NM from the end of the runway or 2.0 DME I-IRK. At 130 knots (is that a valid REF for the J32... I have no idea?), no wind, you'd have to descend at approx 760 fpm to get down from that point.


Are you going to get out your abacus and calculate all this out while descending to the destination? Probably not. But you might have looked at it before hand... during preflight planning or during cruise. You might not figure it to a gnat's a$$ but you could do a few rough calculations, as the AIM suggests, so that have some SA. "Hey looks like there may be some terrain issues. Hey looks like we might needs a little more than a three degree descent here. Hey we might expect to be white over white initially." The descent from the MDA is not an instrument manuever, it's a visual one. You have to meet the requirements of 91.175(c) and, if you want to be safe about it, you'd better have more than just one visual cue available.

cc

 

[Xav8tor]

Clutch,



Thanks for all that hard work. To answer your last questions first, it is a long story. I've worked on a number of crashes in varying capacities on every side of the fence there is, but I've NEVER bought "pilot error" as the "probable cause." In fact, in my opinion, there is no such thing. It's called "Reason's Model." It takes a whole string of holes in the system to bring an airplane down. The problem is usually far up the chain. What I have always done, no matter who I was working for (airline, law firm, pilot, individuals), or even out of my own personal interest when just reading about an accident, is attempt to understand why they occur and how to prevent them from happening again. I had the same philosophy when I was a Director of Safety. When airplanes crash, the root causes (plural) are in the system, NOT the people.



What I, as a plain old individual, for my own benefit, am "fishing" for on a public discussion board, where other pilots may benefit, are answers to why an apparently large number of people interpret 91.175 as they do, and why those who write the regs and design approaches have left such a gaping hole in the system that continues to exist even though there have been similar accidents before this one. I know that the law, which is what the FAR’s are after all, is not black and white, but there must be a clear and definitive answer to these issues.


In the future, in my areas of expertise (and I admit TERPS ain’t one of 'em), I'd like to teach, write a book, and do research. I am not a practicing attorney and haven't even sat for a bar...yet-maybe some day (but I have sat "at" a few though!). The main reason I learned the law and got the JD (law degree) was because when I went to DC and participated in an NTSB crash investigation as the CVR expert for the union (trying my best to keep the crew from getting "hung"), I saw and heard things that made my skin crawl and realized that if I was ever going have a snowball's chance in He11 of "making a difference," I needed to learn the rules of the game in order to play it. Would I do it again? Nope...it cost me far more than my house and if I had stayed put where I was I'd be a (big regional) super-seniority Captain at the top of the pay scale with 15 days off a month and zero debt spending my days off on SoBe. I got back in the airline game as a DOS and got to fly a little more time on the line to boot…the most fun I’ve ever had and gotten paid for it. Then 9/11 came along and well, you know the rest of the story. Me and 30 or 40 thousand other airline employees hit the street. All but a few airline safety departments were slashed in half, or worse. My airline folded completely, and the one they wanted me to transfer to is disappearing at this very moment. Since then, every offer I've had has either been up North or from a startup. No thanks. Even the carrot of a 74 type from one and a 320 from another one wasn't enough to take a chance on an underfunded startup in this economy.


From a purely personal standpoint, yes, as I said before, it would be very gratifying if I could continue to play a role in enhancing flight safety. Professionally, yes, if I did help push through a needed change in the regs that solved a systemwide safety issue, it would be nice to put that on a resume, or at least bring it up in an interview - to offset the gray hair (why do they all want "experience" but only want to hire "young" people?). Finally, as a “Samaritan,” I've had some success doing this sort of thing before and it is really a good feeling. Try it, you’ll like it, but don’t expect much in the way of $$$ or even credit for doing it. Other than teaching, my dream job now I guess would be either at NTSB (but that’s out due to the GS salary not covering my student loans) or lobbyist for an aviation safety organization (ALPA, FSF, etc., yes! ATA or RAA, not a chance!) Sounds like your current position might be attractive as well! Any openings? I can't hit a tennis ball worth a c rap, but I drive a mean RX-8 in the turns and am pretty darn good with my hands (according to my wife and her forerunners).


Regarding 5966 itself, as far as my questions on this board are concerned, I don't have a single one. The facts are all in the public docket. If I could find a better accident to illustrate the problem(s), I’d use it. (AA 1572 is fairly close though). The reports released by the NTSB about the IRK accident, along with the IRK LOC/DME 36 plate, are merely perfect illustrations of the question/issues that I originally posed and wanted the input of knowledgeable members, such as yourself, about. As I posted before, until they opened the docket on this crash I personally had never thought this sort of 91.175 decision could lead to an accident. However, I did know how I understood the reg and the safe way to shoot a LOC without incorporating a VDP: the ALS sighting permitting 100 above TDZE only makes sense on an ILS (but that isn't how the reg is written or how it is being applied by some people and one is too many).


The chart issue was an afterthought, but again, something I had never been aware of as it applies to this scenario. Because almost every airline uses Jepps, as do most pro pilots, why don't they chart obstacles less than 400' high, especially when the obstacle in question is the final segment controlling obstacle and almost dead on the extended centerline? I am almost positive it is that group of trees that precluded a charted VDP. In addition to charting, there is a possibility that there is something wrong with the approach design itself. I didn't work on the nav/chart aspect of the AA Cali crash, but I do recall that issues with the nav info that existed were ultimately used to take a sizeable chunk of the heat off of the crew. I can think of at least two other accidents where the same thing was done.

My approach to every "pilot error" accident is: OK, the pilot may have made a mistake and/or misunderstood something, but what led him there? An ambiguous reg, inaccurate chart, omission in the AOM, negative training, management pressure/corporate safety culture, etc.? More often than not, everyone involved in an aircraft accident investigation sees the final error as the only error. The rest, if mentioned at all, get buried somewhere else deep in the report or reduced to being labelled "contributing factor." In the more enlightened airline safety departments, and at some other developed country agencies, EVERY factor is a probable cause.

Like you, I am now deep into the TERPS, other AFS-420 pubs, and a huge stack of books and docs trying to piece it all together. (More on that later. I need time to "process" all of that info and get some honeydo’s done). Meanwhile, I disagree about 91.175 being clear enough, but do agree about it not being properly applied. Seems to me like most pilots interpret (c)1 as meaning "don't be too HIGH" when reaching DA/MAP. Viz under (2) is assumed here and the ALS meeting (3)(i) as the reg is written, but not, as you pointed out, properly applied, is exactly the question before us.

PS- Is anyone else at all concerned about the differences in Jepps and NACO obstacle charting or do you just assume that if you fly as published there isn't anything to worry about? I've read ebough of the TERPS to know some things I'm glad I didn't know back when I was a II doing a lot of training in actual, but there is something about "controlling" obstacles not being charted that doesn't feel right.

PPS - 130KIAS is the final segment approach speed used by most J32 operators, Vref "over the fence" with flaps 35 varies by weight of course and is somewhat slower than that (I don't have the manual handy) Edit-110 to 112 seems like it was about avg. ref.

 

[Clutch_Cargo]

Fair enough! Thank you for elaborating Xav8tor.

I'm envious in some ways. You have a chance to make a difference that many pilots never have. And if you enjoy what you do, all the better. I've always loved flying but never found much satisfaction in it. I don't think I'd do it again, not as a career. As far as my current position goes... it's not a hard gig to get into but a very difficult way to make money!

I agree with most everything you've said but I do think 91.175 is fairly clear (in contrast to most of the FARs). It states that you must have three things to operate below MDA/DH. But just because you have those things doesn't mean it's safe to do so. You often hear that expression... "Just because it's legal doesn't mean it's safe." I think this is a perfect example. Cat mentioned above that he had never heard of applying the 'descent to 100 above on the ALS' rule to a non-precision approach. While I knew the rule, as written, allows for that application, I have never done it nor do I know anyone who has. You mentioned the same thing, I believe. Clearly, descending from the MDA is a visual maneuver and the ALS alone doesn't provide sufficient visual cues. Descending from the DH, however, can be accomplished on the gages making it possible to do so safely with just the ALS as a visual reference.



So why all the confusion? Well, I think most pilots understand the practical application of the rule and don't consider the other possibilities... the possibilities they don't consider because they aren't safe. To break it down further:

(1) Normal position to land - As you said, most think of this as "don't be too high." Why? Because why would I be low? Why would I be below MDA? That would be unsafe. I'm going to stay at MDA and if I see the airport in time, I'll make a normal landing. If not, I miss. I think that is the thought process of most pilots.


(2) Visibility - Pretty straightforward. How far can I see. If there is a question it usually relates to what visibility, mine or the reported, is controlling. But the answer is right there.

(3) Visual references - Again, not too complicated. Just a list. However most pilots probably only consider the approach lights as a visual cue in conjunction with a precision approach. I completely understand why... I think the same way. Using them alone to maneuver visually just isn't safe.

​

So it seems most pilots don't plan on being below MDA or using the ALS to maneuver visually. This is good. This shows good judgment. Could the rule be re-written to reflect this thought pattern? I'm sure it could. I'm just not sure that is the best way. Often re-writing rules leads to more rules and I'm not in favor of that. Why? Mainly because I don't think you can regulate good judgment. And it presumes people will even follow the rules. No matter how many rules you write there will always be some idiot who breaks them or finds a way around them or... well, you get the idea. If anything, there should be emphasis on teaching that expression... "Just because it's legal doesn't mean it's safe." Here is what the rules says, what it allows. Here is why good judgment says that it might not be safe to do everything that rules allows.


As for the chart issues, I completely agree with you. I haven't touched a gov't chart in probably 15 years and have always considered Jepps to be superior. I am surprised that they don't chart those obstacles. As long as information is logically displayed, I don't think you can ever have too much of it.

Okay, I've rambled enough here. I think I'm starting to get a tan from the light coming from the monitor... this board is addictive. Thanks for the catch on the REF speed... approach speed is what I meant but not what my fingers typed!

cc

 

[TonyC]

I've been a little too busy lately to throw into this discussion, but now that I have a few minutes...

Also, everyone needs to be aware that the lack of a published VDP means there is an obstacle in your way that precludes using one. Of course, most pilots will never learn or know that because it is buried deep within the TERPS and one or two other obscure FAA documents.

Also, when a VDP isn't charted on the plate, that means there's an obstruction that prevents using one (or at least the FAA from depicting one).

To clarify the VDP's publication or it's absence. Your statement that it's absence "means an obstruction exists" isn't exactly correct. Under the current TERPS criteria, a VDP will be charted if there is DME available to the runway AND established at a point where a VGSI (VASI OR PAPI) slope intersects the MDA altitude. VSGIs angles are adjusted in slope with regards to close-in obstruction clearance. But you have to remember, that VSGIs also have a distance limitation regarding obstruction clearance even when in sight. Therefore, the lack of DME or a VSGI will also preclude charting a VDP, even if there isn't an obstacle.

The risk of interpreting it your way is if someone takes it inversely...that they assume because a VDP IS charted, that NO obstacles and or terrain comes into play and they wind up doing exactly the opposite from why they are published, and dropping down too early.

I haven’t gone that deep into the TERPS yet on this VDP issue, but I retrieved that theory from the website of a guy who seems to be an somewhat of an IFR afficiiando ...

Maybe it's just me, but I can't help but be reminded of the humorous series of Holiday Inn Express advertisements.


Xav8tor, I think I understand your purpose and can empathize with your zeal to learn, but you really must be more responsible in your presentation of "facts" in order to maintain any level of credibility. To hold yourself up as somewhat of an expert on a topic, to say "everyone needs to be aware" of something that's "buried deep within the TERPS" (as if you know where it's buried) and then to admit you really got that idea from "Jim Bob's web site" casts a cloud of doubt and suspicion over anything else you might have to say.

I was waiting for a spell of spare time so I could dig through TERPS to find this nugget of wisdom about the presence or absence of published VDPs - - you had me going. Thanks to CatYaaak for sparing me the trouble!


Now, it seems to me you're a little hung up on this matter of close-in obstacles appearing (or not appearing) on Instrument Approach Procedures. Frankly, I am puzzled about your obsession. During a 2-day stretch last week I flew into six airports where I had never landed before. Had I spent the amount of time studying each airport and each possible approach to each airport for each and every clump of trees and stray utility pole that you have spent studying this one site, I would have had NO time to sleep. How could I safely operate in and out of those airports, then? Simple. I adhered to the guidance of 91.175(c)(1), that is, I did not operate below DH/MDA until my airplane was "in a position from which a descent to a landing on the intended runway could be made at a normal rate of descent using normal maneuvers." When I apply the rules, I don't need a satellite survey of every runway. Shoot, my Jepps bag is heavy enough as it is; I don't WANT satellite surveys!



Could it be that you're putting too much into "the investigation interview statements" you used to begin this thread? Could it be that some comments were taken out of context? Could it be that some comments were presented out of context? When examining a particular statement, could it be the respondant misunderstood the question he was asked? Could it be he was just wrong?

Your second sentence claims "a lot of pilots are under the impression that, upon seeing the approach lights during a non-precision approach, it is permissible to continue descent from MDA to 100 feet above the touchdown zone – REGARDLESS of the aircraft’s distance to the threshold." Have you found any pilots on this forum that have that impression?

 

[eddie]

Although this crew may have been comfortable decsending to 100 above TDZE, the CVR transcript doesn't really address continuing below MDA.

I would like someone to touch on the fact that neither pilot discussed leaving MDA, the only altitude that was mentioned was MDA...why is it being assumed that they planned to continue to 100 above. Maybe they went below mins.

The Captain saw the lights 1 second before the radar alt. said 200 ft, and the FO didn't say he had the approach lights until after the radar alt. said 200ft. I'm having trouble buying the fact that they didn't just drop below mins because they were both outside.

Am I missing something really obvious here? I know your discussion on the board is about the fact that a lot of pilots believe they can continue down at any distance...but after reading that cvr transcript, I'm just not sure that is what happened here.

 

[Xav8tor]

Tony,


Did you even bother to read any other, or maybe even all of my posts? I am not trying to sound like a TIP/TERPS guru, but I would like to hear from a few. When I have finished analyzing the TERPS, AFS420 docs, and the myriad of other applicable regs, etc. on instrument procedure design, and talked to a few more guys in the 400 branches at the FAA, and integrated it with the opinions you and others have expressed, I will try and share the conclusion and see if it holds water with those of you here, and elsewhere, who have bona fide expertise in this particular area. Until, and if, that happens, I have asked, if not outright begged, for input from those who might have credible knowledge about the subject to help me (and pilots in general), not take cheap shots up my six for starting and participating in what I hoped would be a potentially meaningful thread concerning aviation safety.


The lack of a published VDP according to some is taken as a clue that there is an obstruction affecting an otherwise normal approach, a statement I took from a fairly well-known website written by a gentleman who, while maybe not infallible, did boil the question down into an understandable form when, at that time, I was looking for a quick answer to get the ball rolling and pointed in the right direction. I'll see if I can dig up the phone number of the FAA guy who is a supervisor in the region that designed that approach who, as I understood him, said something similar to what you are taking issue with, but below is the other quote I was referring to:


"You can use or make a visual descent point (VDP) as a landing aid. TERPs require a VDP for all straight-in non-precision approaches except for procedures with remote altimeter setting, where the descent path is below a required step-down altitude and where it would be between the MAP and runway. No VDP will exist where an obstacle exists. The absence of a VDP serves as an obstacle alert." (bold emphasis mine)


http://www.whittsflying.com/Page7.62All%20Other%20Approaches.htm


I'm not sure of his quals except that he says he is a 10K hour CFI who has taken the time to build a website with hundreds, if not thousands, of pages of great tips, tricks, and explanations on IFR (and VFR) flying. Some may be oversimplified, maybe even incorrect, but visit the site and decide for yourself. I admit I did quote it though and I will, after appropriate research, either back it up or correct (retract) it. As I said, my next move is going deep into the source and interpreting it myself, enlisting free help from the Feds where possible and getting some advice from a few ex TERPS retirees who I've worked with before. If you don't think all the answers to approach design are buried deep in the TERPS and other documents (i.e., beyond the reach and "teach" of most IFR pilots, then instead of taking cheap shots at someone who admits he isn't a TERP/TIP design guru, how about you explaining exactly how the LOC/DME 36 at IRK was designed, why controlling obstacles are charted on NACO but not Jepp, and what each and every entry in Form _ _ _ _ (you know the number of course) is, and how it was determined, and how it affects the design as a whole. Also, why was 91.175 written to allow descent from MDA solely only the basis of sighting an ALS if literally applied (which by the way, the cannons of statutory interpretation and construction defer to over "common sense".) What is the background history of the NPRM (if there was one), or the rationale for any alterations since its original publication? Also, could a controlling obstacle at 1059 feet, give or take a few, located on the localizer just off the end of the runway affect a VDP? If so, how? If not, why not? Does it affect the descent angle in any way, or is that just due to the triangulation of the three points that define it? (some of these ?'s are rhetorical, some not, a few have already been answered).


As for your last two questions concerning the witness statements I referenced, and posted elsewhere on this thread, what context are you speaking of? The pilots, check airmen, DOT, APOI, were asked if it was OK to leave MDA upon seeing the ALS? You saw the answers. Only a couple who said yes expressed concern about distance from the threshold. Did you read what the APOI said about the TERPS? Instead of crossing (as in cross-examination) me, spend a few bucks yourself and get the whole docket, or give me the URL of a place I can upload it and I might just do that, time permitting. Read all 35 pages and come to your own conclusions. Read the rest of the >500 page docket and attachments too. Then correlate the CVR with the FDR. After you do that, then you can talk about putting the question in "context."


I said earlier that this accident was merely an example of what is IMHO a broader system safety issue and I am looking for other similar misinterpretations. When I find them, I will post them. I say again, I am not a TERPS expert. I am however, an expert in other certain areas, and I do know how to properly investigate an accident, examine evidence, ID and address safety problems, and maintain "credibility" by citing reliable sources. In this thread, I am not however preparing an accident report, getting ready to do a research project, publish a paper, or prepare for an argument before the Supreme Court. If I was, I wouldn't be asking questions on this board or making comments purposely designed to elicit responses contrary to what I wrote, to stimulate productive debate, a technique I picked up both in law school, and as an accident investigator, and as a Director of Safety. I saw also it on CSI once and I too stayed at a Holiday Inn Express recently, but only because the Ritz was full.



In any event, asking questions, expressing opinions (my own, and those of others) seems to have backfired on me here. Sorry, I didn't mean to be such an idiot wannabee and/or troll, trying to toy with the minds of all the top guns and widebody Captains. I guess I should just shut up and listen (wait a sec, isn't that exactly what I was trying to do?). Please, give me a few weeks and I might figure it out (with the help of some members here), unless I get my priorities straight and focus on some other things I should be doing rather than persisting in trying to find THE answer to a potential problem that might hurt people I don't even know (and who probably wouldn't take a leak on me if I was on fire).



The FACTS I presented are from FACTUAL reports generated by a government agency, many of which were conducted in a manner that encompassed legal formalities. Everything else was an opinion and sometimes, pardon me, a guess. I thought that was the way people collectively identify a problem and arrive at a consensus solution via the free exchange of information, from pure facts to shot in the dark theories. I guess I should have known better after 12 years of higher education and almost twenty in aviation, half of that in safety. I deeply apologize for whatever the heck it was I did to offend you above and beyond my verbose, pointless, zeal over a trivial, common sense, irrelevant topic.



I plead guilty to repeatedly (about once a year) becoming absolutely obsessed with certain safety issues. I neglect my "day job," family, friends, "chores," and everything else when I get like this. The saddest part is, I never have anything to show for it, other than fatigue, lost income opportunity, and missing quality time with my small family and circle of friends, and large holes in my empennage. Why? Well, it is impossible to demonstrate that whatever I do (heighten awareness, present an argument that was the impetus for a change in a law, policy or procedure, even wrote a brief ten years ago that still gets attention and recently was the main subject of an NTSB Public Hearing on new safety measures they want Congress to pass) did one bit of good because you see, it is almost impossible to prove a negative (i.e., the accident that didn't happen).



Whether it is one's profession or a hobby, or just a nut with an obsession, the questions raised, the answers found, the solutions derived, all of that comes together and may save a life or prevent serious injury one day in the future. Most of time, you will never know if it made the difference, and in those rare instances where you think you do know, no one ever says thank you, there is no bonus in your check, if you get paid for it at all, and someone else ALWAYS takes the credit. Again I am sorry for asking such silly questions and suggesting such absurd possibilities on a subject I obviously have no business even being concerned about. Now that I think about it, you've made me realize I have wasted the past two decades of my life, missed out on irreplaceable time with the people I love, and gone neck deep in debt. I think I'll make an appointment with a shrink first thing in the morning to see if he can cure this obsession. I may still die poor, but at least I won't waste any more time fretting over the welfare of other people who couldn't care less about me, or my well-being. Thanks for directly and indirectly pointing all of this out to me Tony. You might not have meant to do so Captain Driver, but you did me a huge favor Massuh.



PS- In answer to your last question...Yes. And as I've said before, one is one too many.



PPS - Start a thread on anything related to CVR's if you really want to see my obsession and credibility.

 

[Xav8tor]

Eddie,

You've asked some good questions and those answers I have because they are right up my alley. I am limiting my participation on this board to the two questions about 91.175 and Jepp obstacle charting. I posted the OPS group #2 interviews because they perfectly illustrate the problem with the way 91.175 is being applied by a large (relatively speaking within a defined sample) group of pilots. The CVR transcript excerpt was posted to help illustrate the thought process (and everybody wants to see it anyway).

The issues you bring up require some very complicated explanations both technical and legal. I'd be happy to discuss CVR analysis either alone, or in conjunction with FDR/Radar data. I'm just not sure I want to do it about this accident and/or in this thread. It's after 0400. Let me sleep on it. I will say that even though you haven't accounted for time sync and NTSB transcription methodology issues, you are on the right track. Also, the CVR, FDR tab, ACFT Performance, ATC group reports, and more from OPS #2 have to be integrated.

I'll think about it and try to explain what I can tomorrow. I will say that at first blush, it looked like a constant 11-1200 fpm ROD until just before the first impact with no obvious level-off at MDA or 1064. The calls were a little off in more ways than one. BUT this is a first take looking at raw data with no time sysnc and a host of other caveats and that is coming from others who have seen the data, not my own in-depth analysis. I'm just not disagreeing with it, if for no other reason, than I haven't run it yet and it does look like it to me on the first take too.

 

[ackattacker]

This is an excellent discussion, I think, with lots of good points all around and I hesistate to chime in with my regular old pilot viewpoint given all the technical talk being thrown around... but regs don't have to obey the laws of physics and lawyers don't get killed when they get it wrong.

Now, it appears to me that the regs do allow you to do the stupid thing and descend below MDA using the approach lights only on a non-precision approach. This is clearly idiotic. I question Xav8tor's statement that a lot of pilots seem to think this is OK. But I guess some do and some is enough to be dangerous. Apparently this company taught it, but they are hopefuly the exemption to the rule...

This whole descend to 100 HAT has always struck me as bit funny, even on a precision approach. You better know what you're doing. And just to let you know, I have shot more than my fair share of 1800 RVR VV001 approaches (ACK anyone?). The reg reads paraphrasing) "can't descent using ALS as the only visual reference unless red terminating side row bars also visible" and is a bit suspect. I mean, I've used this rule more times than I care to count to get down a little lower but I never really used the approach lights as a real reference to my aircrafts position, only just quick glances to verify lateral alignment. If you take your eyes off your scan for more than a second or so you've lost it for sure, until you get the REAL visual references (terra firma). I think this is pretty common practice, you don't see the ALS and go visual, you see the ALS and *continue*, as in "continue the instrument approach". This being safe because, with the ALS visible, you probably won't run into them. (and I've never seen an obstacle poking *through* the approach lights...) I know this is not exactly how the regs are written but practically that's how its done. Anyone disagree?

So, how do you apply this to a non-precision approach? You don't. I suppose, theoretically, that if you broke out of a non-precision approach and saw the approach light nearly underneath you then it might be tempting and perhaps legal to dive at them in hopes of getting the runway. The same general idea being that if you can see it and it's lit up then you probably won't hit anything between here and there. This is obviously dangerous, and the other way (seeing the ALS 3 miles out and dropping to tree-top level) is even more ridiculous. "Normal rates of descent" applies to both excessively slow and fast, as I believe most of us have been taught. Either way, there are other problems:

1. You can't very well be continuing any portion of an instrument approach at this point. You left all that behind at the MDA. You have no vertical guidance and no guarantee of any horizontal guidance either (depending upon the approach, or course, the location of the navaid, DME, etc.) Non-precision approaches are predicated upon essentially "going visual" to land. This is how we announce it in two pilot crews, is it not? "Runway in sight 12 O'Clock", "Going Visual". If you can't even see the runway, how can you possibly have enough visual reference to actually control the aircraft visually? So really, you have neither adequate instrument reference NOR adequate visual reference.

2. When you are visual you are taking responsibility for your own terrain clearance. I thought most pilots understood this. If you can't actually SEE the terrain than this is a pretty stupid thing to do, if you think about it, but of course we do it all the time since at night we often can't see the terrain when landing. In this case we are NOT relying on the TERPS to protect us we are relying on the same basic airmanship we learned when we got our VFR ratings and a little caution goes a long way. This is why the regs are so vague in this area. It's tough to regulate basic airmanship. I mean, there's no regulation which states "don't land if there's cows on the runway" but we pretty much use our common sense. This is no different on any non-precision approach, whether you see just the ALS, the runway, the whole damm airport--- once you've left the MDA it's entirely up to you to not hit anything and you have to use every trick up your sleave (knowledge of terrain, DME/VDP/GPS, avoiding black inky spots that could be either a lake or a mountain, etc). How could simply having the ALS in sight guarantee that you won't hit anything? Unless you're right on top of it? You can easily run into the ground on a clear moonless night with the runway in sight from 20 miles away. Or how could anyone believe that so long as you see the ALS you are "protected" at 100' (100 feet!!!! it gives me goosebumps!) above TDZE for an indefinite radius.

I guess my point it this, since I know Xav8tor that you are gathering a sort of survey/snapshot:

1. I was never specifically told to not use this rule on non-precision approaches. However, I was *never* taught to. I guess it seemed obvious.

2. It appears to me, that while the rule does seem to allow for a legal descent to 100 HAT on a non-precision approach, practically there is no legal way to do it, since you'd probably have to break some other regs to do so (operation below MDA without adequate visibility, not being in position to land using normal maneuvers and normal rates of descent, operation below VGSI for air carriers, I'm sure I could find some more).

3. Regardless of the legalities, its assinine. It's probably just an oversite on the FAA's part that it's legal at all. But then again, plenty of things are not prohibited but still stupid. It's not specifically prohibited in the regs to get up, spin around in circles 20 times fast, then sit down and try to land the plane, but it's pretty stupid.

4. The reg probably should be changed. There are, unfortunately, people who spend a lot of time studying the regs trying to figure out ways to get away with stuff they probably shouldn't. We've all seen it. And if you have an operator who has an economic need to operate reliable service into an airport which is hard to get into on instruments, they just might decide they've found a "loophole", and teach it to their poor unsuspecting pilots.

 

[Xav8tor]

Ack,

The tech talk is a necessity I guess because it is the nature of the beast. Your plain old pilot viewpoint is exactly what I'd like to see 1000 more of, which is why I asked a while back that people link this thread to other boards that might find it interesting.

Legal isn't safe was something I had to tell management every single day as a DOS. When I said a lot of pilots seem to think this way of applying 91.175 I was (I think) referring to the ratio of people who said that in the NTSB report. As a ratio, it was a lot, but I was trying to be "PC" and not single out this one airline. Of the people I spoken to about it and the responses on this board, two have said it was "legal." The rest used words like idiotic, stupid, insane, retarded, etc.

I earlier alluded to my first ILS to real mins using the ALS to get in. I was the PF as a newly minted FO in a J32. We had held for 20 minutes when the Wx finally came up to 1800, then went back down to less after we were inside the FAF, then up again...you know the drill. Cap'n said stay inside until I tell you to look up. At 200 he said I've got the rabbit, keep on coming, stay inside. Out of the corner of my eye I saw a fuzzy glow. Very quickly we passed through another 100 feet and he said I see the bars, stay inside, keep on coming. I was a little scared, but trusted this guy completely, he was one of the best. About that time, the GS bar on the flight director shoots upward and I pitch up to it, the Captain says runway in sight - look up, which I did just in time to pitch up another 2 or 3 degrees, trying to get out the words "going visual" before the thing just started rolling on the runway, never even felt it touch down or a heard a squeak out of the wheels. He took the controls at 70 knots and I just ran the checklists and nervously smiled at him. I got out and went in the breakroom, sat down, chainsmoked about 3 cigs, and gulped down a quart of coffee before I stopped shaking like a leaf (inside anyway). Since then, I've shot a few more down to mins like that (handflown in the J32 you know) and understood at that point how the reg was meant to apply. We too were legal but also perfectly safe. We flew it by the book, as a team, and knew each other's capabilities and those of the plane and that particular ILS, and had done it in the sim a few times. But buddy you are right, you had better do it by the numbers and know exactly what you are doing, especially in a plane like that one.

Thanks again, Ack for your input and analysis. By the way, your "cow regulation" comment was pretty funny to me. I did some consulting for a regional down in the Caribbean a couple of years ago and that was a really big safety issue they asked me about. At one airport, a low pass was required on almost every approach to clear the cows and goats off the runway. They had a fence put up, and tried a few other things, but the locals kept cutting through to take a shortcut to get to the farmer's market in town. I came up with 3 or 4 solutions, but last time I heard, I don't think they'd yet done anything about it. The most laid back, easy-going, adaptable guy I know almost went nuts after about 18 months down there. Great place to visit, lousy place to live and try to run an airline. The answer to a safety issue you bring up down there is almost always "No problem Mon....ev'ryting be Irie."


Back on topic, still pouring over the design criteria looking for the definitive answer in "English." Hope to have something soon. Also, if anyone has some space on a server somewhere, I could upload the other docs, charts, pics, etc. PM me if you do. I don't have one I can use for this.