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

[nosehair]

is that your pooch? That has got to be one of the funniest pictures I have ever seen in my entire life. I LMAO every time I see it. I swear that dog is laughing, not just panting.

...oops, FN, he thinks that's your DOG! MMWAAHAAHAAaa...

 

[Illini Pilot]

the 100 rule is only on a precision approach

down to 100' feet, two miles out is not a normal descent to landing

let me clarify about that...

that isn't an FAR rule...but think about it? are you REALLy going to drop down to 100' if you are on a VOR approach without a FAF, you are within 10 and are cleared and established? no.

(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 following visual references for the intended runway is distinctly visible and identifiable to the pilot:

(i) The approach light system, except that the pilot may not descend below 100 feet above the touchdown zone elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are also distinctly visible and identifiable.

only a precision runway is going to have the ALS, unless you are doing it to a prec. runway that also is served by a NP approach. so when i said it only applies to prec. approaches, i misstated what i meant to say. if you are shooting a VOR approach, hit your VDP or whatever and only see the ALS, going down to 100' abv TDZE is perfectly fine. however, you CANNOT do it 2 miles out, that violates:

(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;



just remember:

 

[AV80R]

“The final, and perhaps most, interesting thing, one that really threw me for a loop reading these factual reports, is that the NTSB seems to have found that the crew of the same flight under similar weather conditions the night before the accident almost did the exact same thing and had to do an abrupt pull up of sorts to avoid hitting the trees at about the same place.”

Would you please show us your source here, where is this information coming from?

Isn’t it funny how good we all are at speculating on how things should have been done? Would we still be such experts had we been in their shoes? Just wonder…

 

[WMUSIGPI]

I have to believe fatigue played a part in this. I know coming in at the end of a 14+ hour long day, trying to pick out the airport lights from the rest of the city lights especially on a non precision approach is tough. I have seen lights I thought were the runway only to realize a couple seconds later it was a street or something else. It would be really nice if the FAA would recognize that it's foolish to permit us to work potentially a 16 hour duty day without any mandatory breaks at an airline yet jobs like truckers only can work 10 hours and must take a break in that time.

 

[Xav8tor]

OK Nose, I'll bite. You mean it isn't his dawg? Or even a dog at all? My near vision isn't even close to perfect but my Photoshop skills are OK. It's only a 6.06 kb 92 dpi GIF, but when I blow it up and enhance, it still looks like a dawg to me. Is it a mask, costume, digital fake? Come on man, don't keep me hangin. Oh crap...now I get it. Are you saying that it is his biatch? I think she's cute if that's the case.

Seriously, I gotta know about that pic. It is just way too funny. BTW, the waveform and spectrogram ("voiceprint") on my current avatar is a short half second or so human sound, but it isn't speech.

 

[FN FAL]

...oops, FN, he thinks that's your DOG! MMWAAHAAHAAaa...

"But I thought you said that your dog did not bite?"

"That is not my dog."

 

[FN FAL]

OK Nose, I'll bite. You mean it isn't his dawg? Or even a dog at all? My near vision isn't even close to perfect but my Photoshop skills are OK. It's only a 6.06 kb 92 dpi GIF, but when I blow it up and enhance, it still looks like a dawg to me. Is it a mask, costume, digital fake? Come on man, don't keep me hangin. Oh crap...now I get it. Are you saying that it is his biatch? I think she's cute if that's the case.

Seriously, I gotta know about that pic. It is just way too funny. BTW, the waveform and spectrogram ("voiceprint") on my current avatar is a short half second or so human sound, but it isn't speech.

I scammed the photo off the net somewhere and cropped out the part where he had a bright neckerchief. It's not your fault, you can't be expected to know the what, where, how of everbody's avatar.

 

[A Squared]

Uhhhh, guys, Read the NTSB's preliminary report. Unless information in the preliminary report is completely incorrect, this accident didin't have anything to do with descending to TDZE+100' with the approach lights in sight. According to the preliminary report, the airplane crashed 4 nm from the runway. Now think about it, how likely is it that you'd be at MDA, 4 nm from the runway, and have the approach lights in sight? The FAF is only 4.1 nm from the end of the runway and the FAF altitude is 2500'. MDA is 1320. It would have to be a pretty steep descent to lose more than 1200' of altitude in 0.1 nm. They'd have to be in an almost vertical descent, (63 degree dive) or more likely, they were well below the FAF altitude when they crossed the FAF. That seems to point to them either being completely lost on the approach, intentionally descending below minimums 5 miles out, or possibly having both altimeters set incorrectly. The most obvious cause of misset altimeters, not switching form QNE to QNH when descending through 18,000' can probably be ruled out as the local altimeter setting was 29.95

I'd be interested to read the factual report. It hasn't been posted on the NTSB's site at this time. Any links to it?

 

[Xav8tor]

Illini... Don't all instrument approaches have an FAF of some type, and are there not runways with only non-precision approaches that have some type of ALS? Also, in this scenario, there was no published VDP and the profile flown was "old school" chop and drop, not the newer stabilized approach style. I personally prefer the old way myself on a LOC/VOR/NDB etc., even in a VNAV capable aircraft.

Your thinking that using the ALS as a reason to continue descent should perhaps only apply when on an ILS has some logic to it because if you are on the GS, you are protected. On a LOC/DME, if the MAP is at the threshold, as in this case, and you were making the miss or continue decision upon reaching MAP, the ALS wouldn't even be a factor because you would be on top of it if you are still, as you should be, at MDA until you see something on the "list."

That brings me to what I see as a possible conclusion to consider. Where you do not have a GS (i.e., a non-precision appr.), and you don't see a VASI/PAPI yet, shouldn't the other visual reference requirements only be considered upon reaching the MAP or VDP, and not before? What I am looking for is something, either written or a common practice that says what common sense tells you: Stay at MDA until you have a vertical reference, which the ALS isn't. Literally read, 91.175 and 121 regs using the same language seem to infer to many pilots that you can descend to 100 above the runway upon seeing the ALS, and only the ALS. They way I've always applied those regs is more a part a of the land or miss decision process at that point in time/space, and except for spotting the VASI, not before (unless there just isn't one or it is OTS).

Remember, there's another reg out there that says you must remain on or above the VASI or GS. On an NP approach you will of course at some point be below the VASI's GS at MDA, but one you intercept it, you must stay on/above it. Obviously, the problem is where you have low viz and see the ALS, maybe even the green threshold lights, but being further away you don't have the VASI and there is no VDP. At what point is it safe to leave MDA and what are you basing that upon?

 

[A Squared]

Illini... Don't all instrument approaches have an FAF of some type,

No, they don't. In the case of a VOR or NDB on the field with no DME there is generally no FAF

and are there not runways with only non-precision approaches that have some type of ALS?

Yes, plenty of them. I don't know where Illini came up with that but it's wrong.

 

[Xav8tor]

A2'd

You got me there - in a literal sense anyway. I mean, if you want to split hairs, there are plenty, well some anyway, I'd have to count 'em, of on field VOR/NDB's with FAF's (intersections, etc.) off field. I was just trying to make the boy think using the Socratic method without coming right out and saying "go back and read some more." Man I got my six shot off on another thread for trying to do that politely!

Good call in any case, now back to your other response, I got a long one I hope helps coming up in a minute. I had to go back and re-read some stuff to get your answers. The wife says I need to get some work done today too.

 

[Xav8tor]

A2’d…The NTSB prelim is something they toss together quickly before the hole even stops smoking. Yep, it leaves out a lot and they often contain errors. This one is no exception. The factuals released have all the usual group reports, charts, maps, tables, etc. I don’t have it in front of me, but the impact was almost dead on the centerline a little over one mile from the threshold (1.2 nm I think). According to the FDR and CVR, they configured before the FAF, crossed it, did around an 1100 fpm descent hitting MDA around two miles out, all SOP in the J32. The thing is they kept on going past MDA. Just a second or two after passing MDA, the CA saw the approach lights and the FO said “in sight…continue,” and they did, right into the trees. Along the way, the GPWS and radar altimeter alert systems in the ‘Stream were working properly (doesn’t seem like the new enhanced ones would have made a bit of difference in this case). The altimeters were set correctly and they were dead on the centerline.

The NTSB is (so far) doing a great job on this one because they picked up on the “continue” statement and pursued it. Although it doesn’t seem like they were going to stop right at MDA anyway (looking at the FDR), and may have intentionally gone a little lower than the 356 MDA with a 300 ceiling, they had armed the FD alt mode at MDA and probably did the CWS thing while ducking under some more, but upon seeing the ALS they cancelled the FD immediately after the FO said “continue.”

The ops group interviewed a bunch of pilots, check airmen, instructors, the POI, and his assistant (APOI). About half the group said it is SOP to leave MDA upon seeing (only) the ALS and going on down to 100 above TDZE. A few indicated concern about doing it too far out. The POI, who I think is the only one to nail it (using logic, not just spouting a reg word for word), said you can do that only if you also can see and intercept the VASI. The APOI got it assbackwards and said when you see the ALS at MDA, drop down to 100, then when you intercept the VASI, you follow it on down. Shoot, picking up the VASI at 100 feet means you are just off the end of the runway…when most guys (except lowriders) start going below the VASI to begin their “flare.” The APOI also claimed the TERPS assured obstacle clearance when you leave MDA out there if you see the lights. Say what????

The confusion doesn’t stop there. The NTSB says they showed the APOI a JEPP plate with an obstacle on final at 1027. I don’t see it on my copy, and Jepp says they don’t do that anywhere, but I do see one at 1059 on the NOS. Here’s the other mind-blowing quote: “He was asked if he was aware of an incident at IRK on the night before the accident when a Corporate Airlines crew had to climb to avoid colliding with a tree using the same approach procedures as the accident crew.”


I didn’t start this thread to speculate on this particular crash or second guess the NTSB, or the crew either, but this accident is illustrating what I think is a serious flaw in the system. The NTSB does a fine job, best in the world at it outside the military maybe, but their goal in investigating an accident, and what the airlines, manufacturers, safety people, lawyers, regulators, teachers and consultants like myself need to know about causation and how to act upon those factors is different, much broader and even deeper (another topic altogether). The NTSB “bluebook” is absolutely never the whole story and certainly not the end of it either.

What I am concerned about, professional interest aside, is for my own personal benefit, and maybe yours too. I wonder how many of my former students, whether when I was an active CFII or when I lecture, think seeing the ALS means go to 100 agl – period? I never taught it that way. When it did come up, like I said, it was in the context of deciding whether to miss or not. I’ve chased the rabbit on an ILS enough times that I don’t pucker up anymore doing it (still about the most clothed fun I can think of handflying one of those though). But on a non-precision approach, I have never given this (seeing ONLY the ALS and dropping to 100 above TDZE per 91.175) a thought…until now. Now I can’t get it off my mind, and what’s up with Jepp leaving that obstacle off of their plate?

PS – The NTSB is investigating this crash as a major, but they aren’t treating it like one in some respects, all at their option. It doesn’t look like there will be a public hearing, just the board meeting to adopt the final, and they didn’t post the docket – you have to call and ask for a copy (over 500 pages not counting pix and the FDR data) or you can get the CD. They will probably post a lot of it along with a few other goodies after the board meeting (later this year?), which will also be a webcast. They do all of them that way now.

 

[MTpilot]

What do y'all think?

I teach my students that if you can see the approach lights you can go lower (100ft) the idea being if you can see approach lights, you can see obstructions as well. So you aren't "guaranteed" anything.

 

[EatSleepFly]

I teach my students that if you can see the approach lights you can go lower (100ft) the idea being if you can see approach lights, you can see obstructions as well.

If you're talking about a non-precision approach: No way, absolutely not. What about at night? What about wires or unlit temporary obstacles? That's a pretty scary statement, actually. 100' isn't much, and I don't want to be there on a non-precision approach unless I'm looking at the runway/threshold itself, personally. Now, of course, a precision approach is a different story.

 

[A Squared]

Oh, I didn't realize those were rhetorical questions.


Also, I'll have to withdraw my comments about it not being related to descent to TDZE+100. I know that the preliminary is just that, preliminary, but I assumed that very basic info like the distance from the runway to the crash site being 4nm would be correct. Bad assumption, apparently.

Regarding the 1027' obstruction, it is depicted in the airport diagram in the lower left corner of the NACO chart, slightly east of centerline.