Glideslope and visual approaches

[beytzim]

Everyone above has said very good comments. I can't argue with them. You are all right and I will be honored to fly with any of you.

However, one guy asked how many 91/135 guys crash vs. 121 guys. Well, the stats are actually statisically identical among Turbine aircraft! (accidents per 100000 hours: .21). And then he mentions that customer service is a priority in the 121 world. You're kidding right? Like that Northwest airplane that left passenger in DTW 8 hours in the airplane 50 feet away from the gate. Or how about the covert way after 9/11 when airlines were cancelling the first 4 flights of the day cause of low loads and combining everyone on the last flight of the day. I could go on all day. There's a reason why people spend $20,000 to fly a Lear 55 when they could get the same flight for $600 on an airline - it's CUSTOMER SERVICE.

91/135 guys aren't more dangerous than 121 guys - we just use our brains and excercize our flying skills more than you do! Jealous?

The point of the discussion is this: When the S*@t hits the fan, I'll know that among my bag of tricks I can land on a 4000 foot runway with a 129 knot Vref. I don't make a habit of ducking (The last time I ducked was about 6 months ago)- but it is a skill that is valuable to have.


Happy Flying,

beytzim

 

[SentryIP]

Original Discussion?

Hey All,

I've been a military pilot my whole flying career and all our airplane manuals and instrument procedures emphatically state not to duck under the glide slope to touch down on the numbers. The evidence is there and plain to see. It'll bite you in the @$$ one day. I'm sure all the pilots who landed short thought they had the skill to accomplish it successfully. Please excuse me for not being aware of the animosity between Part 91/121/135 pilots. The discussion is not about who's the better pilot, but about the pros and cons of the duck under technique of as a "standard" procedure. Let's stick to the topic? Fly safe.
SentryIP

 

[Michael Knight]

I have really enjoyed learning from this thread! All training is not alike and for good reason. I can't see a reason for 121 types to duck under glideslope to land on the numbers but then again I don't have much experience with this - that is why I like this thread.

My military training pushed visual approaches / landing patterns to land on the numbers. I'm guessing Sentry is an AF type and MOST AF planes and missions don't call for landing on the numbers. Naval training teaches it early on because many of our pilots will later land on floating runways and well, probably because that is the way we have always taught it. So, I think you'll find many coming from an aircraft flying to very short strips and/or doing assault landings more apt to fly visually to the numbers. I'll just have to remember not to land a big civilian plane like that

-Mike

 

[Lrjet55]

This will someone mad.

This comment is just to add to Beytzim comment regarding accindents among 121/91. The actual difference according to Business and Commercial Aircraft magazine is the male/female aspect. (I am trying to find the specific article to show you guys so I don't come off to be a total @$$).
The FAA studied accidents/incidents over the past 14 years breaking them down into two basic groups: Mismanagement of aircraft and Poor descision making. After all the data was compiled the evidence became increasingly apparent that there wasnt a difference in corporate to airline pilots (althought there was a little disparity, Ill let you guys guess which way) but the actual difference was between male and female pilots. According to the survey a male was more inclined to make a poor descision i.e. flying through a thunderstorm or into icing where as a female pilot was more inclined to cause an accident due to poor piloting skills (bouncing a landing or stalling after rotation). Again this is all factual data and as soon as I can find the article I will post the link. There you have it boys annd girls.

 

[avbug]

There is little point getting into a pissing contest over operating regulations. Different areas of employment will be subject to different parts of 14 CFR, and that's it, period. It doesn't mean one pilot is better, more skilled, or adept. Pilots may not operate outside the bounds of the FAR which applies to their operation.

However, to respond to a previous comment:

"I'm just wondering about that snowy, icy day on a short runway, when I end up in the opposite overrun by "500-1000'."

If the runway is questionable, don't land on it. Refuse the trip. Someone mentioned upsetting clients or owners. Who cares? Many times I have stated that I can't use a particular runway, can't carry an extra person, can't fly after a certain time due to heat, etc. That's a responsibility of the pilot.

Remember that you can be legal and not safe, and safe, but not legal. Unless you are both legal and safe, you need to seriously consider bagging or altering the flight. It's not worth losing your life, or your certificate. End of story.

If you can't get stopped in the useable runway (forget the overrun), you shouldn't be landing there, period.

I can tell you that having flown for various certificate holders, as well as emergency operations of various types, I've never seen a flight that MUST be made. I've seen a lot of flights that are certainly important, and sometimes lives depend on the decision to go. However, on a number of occasions I've taken the responsibility for making the decision not to go, in the interest of the safety of the flight. Even critical operations help no one if you get killed or crash the airplane. No flight must be made.

If the runway is too short, download, find another runway, land some place else, or don't go. I don't care what rules you operate under; this is universal. It's common sense. It's regulatory. If it's not safe, don't fly, period.

 

[BluDevAv8r]

Ok....here's my take on this issue. I believe its often misunderstood, just as this thread is showing. The ILS brings us to 200 feet HAT (typically) at the middle marker. At that point, the ILS guidance is no longer acceptable for Cat 1 usage. We must maneuver visually from this point. If you DID fly the ILS glideslope all the way to the ground, then you would hit the ground theoretically at the 1000 foot marker. That does not take into account the flare/float. The TDZ is the 1000 foot marker plus 1000 feet, as far as my airline is concerned. Thus....I aim for the big white blocks and expect to touch down somewhere in the next 1000 feet, give or take.

As far as flying the ILS on a VISUAL APPROACH, the only requirement that the AIM (and my airline's ops specs) state is that you maintain at or above glideslope and at/above the VASI/PAPI.

"Ducking under" PRIOR to the middle marker is very bad. There is really no such thing as "ducking under" after the marker since obstacle clearance should be assumed if you maneuver safely from 200 HAT to landing. Now....bottomline is....if you see nothing at 200 feet, you MUST go around, no ifs, ands, or butts. If you continue....you're not only breaking a reg but you're putting your passenger's and your safety in jeopardy. Of course...we all know 91.175, so there's no need to discuss that.

I won't even touch this 91/135 vs 121 pissing match. Its silly.

Bottom line is....at MM/200 HAT, you are visual....since GS guidance isn't accurate. Do what you need to do at this point to make a stabilized safe landing in the TDZ.....either using the AIM definition or using your operator's ops specs.

-Neal

 

[avbug]

Neal,

You are quite correct that a Cat 1 ILS is not approved for use below, and not flight checked for use below, 200' above the TDZE. The question then arises as to other glide slope guidance. A visual approach slope indicator angle of any variety (PAPI, VASI, etc) may not be coincident with the glide slope angle established electronically. However, a pilot landing via an electronic glide slope is obligated to remain at or above the glideslope until it is no longer servicable (200' for Cat 1, as covered), and then to remain above visual glide slope guidance where available.

In any case, if one is established in a stabilized condition for the duration of the useable glideslope, ducking under from that stabilized condition does not necessarily represent a safe or proper operating condition, and even in cases not enforcable for violation of glide slope or guidance issues, FAR 91.13 still applies.

 

[bobbysamd]

Going below DH

I have a question, then. Just to clarify in my mind, can someone explain the business about going down another 100 feet after hitting DH?

As Neal said, I always understood that Decision Height means that at that point you DECIDE if you will land or take a miss.

Thanks in advance for all responses.

 

[bigsky]

Im assuming that by referring to going below DA by 100 feet you are referring to 121.651(c)3 or part 91.175(3)?
These can vary according to op specs slightly but basically you need 3 things to land.
1) the flight vis is not less than prescribed.
2)continuously in a position to make a landing in touchdown zone using normal descent....ie
3) at least one of the following is in sight...
A) the approach light system..( any version of) if visible you can descend to 100 feet above touchdown zone elev.. if you pick up the red terminating bars(alsf-1) or red side row bars (A.L.S.F. 2 Lighting) that counts as a landing reference and if you meet 1/2 above you can continue to touchdown.

 

[bobbysamd]

Approach mins

I was thinking in terms of Part 91, which is what I knew best. Good answer. Of course, if you have inop components you raise the mins as provided in the NOS chart or Jepp table on your plate.

Thanks. I just happened on this thread and hadn't thought about it since I've been out of flying.

 

[beytzim]

Good Points. I'll add one more comment. An individual wrote earlier on not to even try to land on that runway if it's too short.

True.

However, many airlines have low speed vs. high speed abort procedures. Usually above 80 knots, one may only abort for certain things, while below 80 knots, you can abort for anything. One may say, if you can't abort for anything prior to V1, you shouldn't go at all. Good, that's my point. Judgement plays a role here - some of us have it, some don't.

Certainly you can abort below V1 for anything and still have enough runway (via BFL numbers). Obviously, the airlines determined that many high speed aborts result in overruns. So they minimized high speed abort for only really serious abnormalities.

Ok, the same thought process can be said about ducking INSIDE the MM. Yes, your numbers say you can easily make it. But, and it's a big but, another 500-1000 never hurts. Big airplanes have the laws of momentum preventing them from ducking - thus the seriousness of unstable approaches. However, airplanes that are small can lower the pitch a little and still be stabilized. Since many corporate airplanes land in short runways (with the same approach speeds as the big airliners), ducking is a required skill.

Fun subject, beer anyone?

beytzim

 

[xrjpilot]

landing distance

For the preflight planning that is required and provided by a dispatcher or the pilot themselves,

the landing distances calculated for a part 25 certified transport category aircraft include

1) crossing the approach end of the runway at 50'
2) on Vref for the weight of the aircraft
3) landing in the touchdown zone
4) using wheel brakes and ground spoilers, NO TR's
5) dry runway

Hope this helps

 

[Focus]

Quack Quack Smack

Ive flown both 135/121 ops. So have alot of other guys/gals who are now flying 121ops. The management that puts the heat on you to deliver in 135 ops without regard to regs. surely is not trying to enhance your career. And believe me, if something goes wrong they will be one of the first to throw you to the wolves.

The debate on who is a better pilot in regard to the operation is totally ludicrous. Its one thing to carry some more speed to the runway in extremely gusty conditions where wind shear is a factor, but ducking under the glide slope will really not save you anything. Boeing has done numerous reports on this issue and Im sure if you call Seattle they will be happy to provide you with the info.

Anyone can duck under a glideslope at any given time and subject themselves to many possible violations. All Boeing or any other authority needs to do is pull the Quick Access Recorder, or other pertinent related reference material and you could find yourself in alot of trouble given the right set of circumstances.

Enough on that. I really dont think there is any reason to duck under the GS unless your in an emergency situation and your forced to land on a shorter runway then optimal. If you get to that point you probably made alot of bad judgements in your flight planning so what else really needs to be said. I cant think of anyone who flew by the book and found themselves in this situation.

Subjecting passengers, yourself, ground personnel or even the cargo your flying to these cowboy maneuvers is hardly what I would call customer service. Your only hurting yourself in the long run. Stay Stabilized with a firm landing in icy conditions and you will be all right. Additionally, bring the aircraft to a complete stop on runway in icing conditions before trying to make a turnoff.

Hope this helps.....

 

[AWACoff]

Hold the phone...I may be smoking crack but the last time I checked, Cat 1 ILSs are flight checked to 100 feet above TDZ. How else are you descending once you have met the criteria at DA to go down to 100ft above TDZ? Please tell me I'm not a crackwhore!

 

[Acestick]

This is kind of related to the question.....

When shooting an ILS and breaking out above the DH, you can then land visually...And part 91 does not specify in the TDZ or whatever, so in theory you could go below the glideslope while in VMC...

Just don't do it on a checkride...I was at a seminar regarding rides and the examiners covered many errors they regularly see. And one of the problems that they all agreed on was regarding applicants ducking below glideslope after breaking out around 200 or 300 feet above the DH. Even thought they are in VMC at that point, the glideslope is about 3 degrees, and going below it is not the smartest thing to do, even though it can be done with reasonable safety in a light single ( A really short field and a fast approach speed )

I'm not sure if its considered illegal or not, or if it is directly addressed in the regs or aim...But I do know that it doesn't look good in a ride when you are trying to impress the DE