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.