30 replies to this topic

[DEFCON]

Don

To your point; it would appear that ‘performance’, a subject that was never well understood by the average pilot, continues to be even less appreciated today. Without considerig the approach itself, the old discipline of landing on target (1000’, on speed & centerline) has been superseded by something like; get it down softly…regardless?

[Don Hudson]

First, so far as understanding "performance" by line airline pilots, I think that there isn't much that one needs to know. One needs to keep to the stabilized approach criteria and plant the airplane in the TDZ and if one isn't doing that or can't due to circumstances, one goes around.

One can't be thinking, "an extra knot over Vref+5 over the threshold is going to cost me an extra 200' of runway"...one simply has to fly by the book. If one knows what one can "get away with" and routinely out-guesses exceeding the stabilized approach limits using these rules-of-thumb then one will use that standard instead of keeping it in one's back pocket for an emergency.

I know this for a fact: high speed, high rate-of-descent events are in the data - lot's of them, and all the time...speeds at Vref + 15kts to 30kts, no headwind for example. Where does the justification for that kind of exceedence come from? The only way is to fool oneself into believing that one knows more than the test pilots and engineers and that one has "always done this without a problem". Almost always it works out because of the margins which accomodate average flying ability (that's in the certification stuff...I'm not making unkind remarks!), but then it becomes habit instead of having something in one's toolbox for emergencies, and habit is what we all resort to when under stress.

I know a couple of carriers now who have moved the AAE (above airport elevation) altitude by which the approach "shall" be stablized to 1000ft. In other words, they got rid of the "500' AAE in VMC". It has been demonstrated using FOQA/FDM data that neither time nor fuel flow are significantly increased, "significantly" being the operative word. Now, the argument can be made that any increase in something that has been shown to be "safe" with a reduced margin is, in the present environment, difficult to counter. The argument for requiring a go-around has been, in my experience, interestingly almost as difficult, the argument "against" being "go-arounds are risky", and "there have been a number of accidents resulting from botched go-arounds". I have heard this said.

Second, the argument continues to be made that "the runway is long", and/or "the taxiway is 7000' down towards the end of the runway", (the stupidest argument I've ever heard was that the airplane "had a big wing, which only means that the airplane, not the pilot, is in control).

While it is blindingly obvious that such arguments are specious should an overrun occur, they do continue to be "mind-sets" on the part of those concerned with time, productivity, cost and operational advantage and, as always in this business, there are reasonable (I'm not saying legitimate) arguments that can be made for this approach, even on the part of flight crews. It's complicated.

What the data indicates is, the risk-reward equation (push the approach stabilized limits in favour of reduced fuel flow/time), simply is not there - it is a myth; the data does not support such an argument, especially when the cost of one minor overrun (such as at Fort Nelson a few weeks ago) in terms of reputation alone should be part of the equation. Even after a minor, (avoidable) event, there can be insurance company examinations, TC audits on operations, potential damage to equipment, the cost of the due diligence of pulling crews off the line for re-current sims before putting them back to work, etc etc.

The $ amount saved by pushing stabilized criteria varies but narrowly, (obviously depending upon equipment too)...my sense for a twin (B737/A320 type, and without formal research) is between 20 and 90kg and less than 1 minute if one is keeping the speed and rate-of-descent up and thrust back near idle with delayed flap/gear extension.

The present trend towards using only idle reverse thrust in favour of just the brakes has not been verified using FDM/FOQA data even though it is a natural question to ask of a safety program which as huge amounts of real-time operational data. In fact, one way to examine operational savings is through such data so that an informed decision and not just an experienced opinion alone can be offered.

I think it is true that given all factors, we prefer to put the airplane down softly...I have some float time doing just that, (with the same justifications! I also have the opposite experience...). But the performance data to which you refer is built upon planted landings with a very short flare. Flare time from 30' to touchdown, when stated in the FCOM, is usually around 5 or 6 seconds. Any longer and one is floating, at 200+ feet-per-second.

Because the data can accomodate some slop, one can put the airplane on relatively smoothly and still within the TDZ of 3000ft, (preferably the first 1500ft). But even if not, so what?

Don

Edited by Don Hudson, 17 February 2012 - 03:21 PM.

[Rich Pulman]

Don Hudson, on 17 February 2012 - 08:59 AM, said:

While the report mentions a steep cockpit gradient I'm not convinced that we could view this just as a "cultural" accident. Non-stabilized approaches which don't end in a go-around and continue well past stabilized approach criteria "because the runway is long", "pride" or other reasons which made sense 30 seconds before touchdown, aren't limited to areas of the world which we sometimes might view as "third world countries".

Although my experiences in India are now fading into oblivion, I do have specific memories where the "cultural" issues leaked through. In one case, I was PF doing the approach & landing into YYZ with an Indian F/O and our CP (ex AC pilot) in the jumpseat. Our company had mandatory "stabilized" callouts at 1000' and 500', but we didn't have to be stabilized until 500' in VMC. On this approach, the F/O called "stabilized" at 1000' even though we weren't. When we got to the gate I gently asked why he made that callout. He told me that if he was flying with an Indian Captain and he didn't call "stabilized" that he would have subsequently been verbally and possibly physically abused, and his chances for upgrade would be severely reduced.

Many times we hear rumours and second/third hand stories of the cultural issues out in the wide wide world of aviation. Sometimes they are true.

[hollywud]

You'll notice that at 35 seconds the windsock shows a slight tailwind. Unless windshear was evident on the approach, full flap should have been used. If windshear was indeed reported, and he elected to use a lower flap setting as required by Airbus, it would beg the question why he chose to land downwind. Thankfully no one was hurt - but I'm sure there were a couple of bruised egos.

[DEFCON]

“First, so far as understanding "performance" by line airline pilots, I think that there isn't much that one needs to know. One needs to keep to the stabilized approach criteria and plant the airplane in the TDZ and if one isn't doing that or can't due to circumstances, one goes around.”

I liked the remainder of your post, but on this point, I don’t believe we’re going to agree?

It became fairly obvious early in the Dryden investigation; no matter the airline, the type operated, or the experience level of a given pilot, there was an almost universal lack of performance based knowledge? More concerning was the reality, the misinformed were operating their aircraft in different manners believing, they really did understand? Therefore, it wasn’t much of a stretch to conclude, a hundred good reasons existed for an ATP to thoroughly understand ‘performance’ matters.

At a minimum, possessing a fairly thorough understanding of performance would lend support to the notion of proper TDZ discipline, wouldn’t it? When a pilot has more than a casual background appreciation of the subject, he’ll better appreciate the consequence of the extras; adding a few knots for one reason or another, or making a soft touchdown the first priority, etc.

[Don Hudson]

I think I may be confusing certification standards with performance DEFCON... One doesn't necessarily require knowledge of the former, (twin performance vice 4-engine performance, or landing distance requirements, etc) but one needs both knowledge and an innate sense of one's airplane's performance.

The point I failed to make well was, aircraft performance is largely though not exclusively upstream of the decision-making process in daily operations. One flies airliners "by-the-book" (I'm not saying anything you don't know, but merely explaining why we likely agree on all points!), and does not need to pursue in-depth knowledge of aircraft performance to ensure an operationally-safe performance envelope. One needs to know one's FCOM thoroughly and where, when operationally required, to find the appropriate performance data.

The designers and test-pilots have done the performance calculation work, and neither the manufacturer nor the regulator (nor employers) expect that line pilots will operate outside such performance numbers, not, at least, without substantive reason.

Knowing how performance numbers are derived may be of some help in some circumstances. For example, to use the Airbus-type Landing Distance Without Autobrake landing distances, one needs to know that in arriving at these numbers, the airplane was (for all practical purposes) not flared, and at touchdown, full pedal deflection was applied until stopped. Now these numbers are used in landing distance calculations for abnormals, and the expectation is, such techniques are not used in normal operations!

The larger point is, thorough training and recurrent training should provide sufficient knowledge, reinforcement of habit and understanding so that knowledge beyond/behind the FCOM performance data should not be required.

The corollary to this is, it is the expectation (and requirement) that, for example, a stabilized approach is flown, and, if outside stabilized criteria, performance numbers are not applicable and one is "on one's own", so to speak.

What I will observe, and what is raised by Moshansky is, even FCOM data can be confusing to use and/or difficult to locate or interpret. I don't think there are too many of us who have not had this experience and done a lot of hangar-flying based upon varying interpretations of manufacturer or OAL-supplied data! I can even recall once when I had to call dispatch because the restrictions on my airplane referenced in the MEL were not available except to those with the MMEL! What a mess that was and interpreting it when it was finally faxed to us was an even greater mess. I couldn't imagine how the arguments would go in court if anything went wrong. In fact the entire day was a wintry mess with all kinds of challenges and some failures and I'll leave it at that...

Knowledge of how much distance is added onto nominal landing distances by increases in speed over Vref +5 (or Airbus' Vapp), could count on challenging landings where things may have got out of hand just a bit and an adjustment can be made to braking, use of reverse etc.

The very fact that there are large factors built into landing data, (we could equally be talking about cruise altitudes/Mach, or takeoff performance speeds and distances and even contaminated runway performance) does not mean that the performance numbers are wrong or too conservative, it just means that through industry experience, the requirement for such factors has been demonstrated because none of us are test pilots and the industry cannot and does not expect such unique standards from the aviation system.

I think your comments regarding a "universal lack of performance based knowledge" (as evidence early on in the Dryden investigation) is accurate, for the times.

From the Dryden Commission Report, (the entire Moshansky Commission Report is now available at http://epe.lac-bac.g...sky1992-eng.htm), the following supports your view:

"The following information is from CASB report no. 86-A60024 . On
July 20, 1986, a Boeing 737 was taking off from Wabush, Newfoundland,
when, as the aircraft speed approached V„ a bird was ingested by the
left engine and the engine lost power . The crew rejected the takeoff, and
the aircraft came to a stop in a bog 200 feet beyond the end of the
runway . No one was injured in the occurrence . CASB determined that,
because the runway was wet, the distance required to stop the aircraft
exceeded that which was available . Pre-flight performance calculations
did not take into account the effects of the wet runway . Such calculations
were not and are not required by regulations. CASB also found
that existing aircraft flight manuals do not provide data that take into
account the effects of wet runways on accelerate-stop distances .
The "safety action" portion of the CASB-produced report of this
occurrence states the following :

In view of the absence of certificated performance data and the
apparent lack of knowledge on the part of flight crews regarding wet
runway takeoff performance, the CASB recommends that :
The Department of Transport revise air carrier procedures
involving wet runway take-off operations, in order to provide a
margin of safety comparable to that for dry runway operations .
CASB 87-45

"The Department of Transport require air carriers to improve
flight crew knowledge of the effects of wet runways on take-off
performance and the means available to flight crews to provide
a margin of safety comparable to that for dry runways .
CASB 87-46

Aircraft Performance and Flight Dynamics p.367, Moshansky Commission Report"

But the Report also states in the same Chapter but a bit earlier:

"The fact that the experienced crew of C-FONF departed from the
Dryden airport terminal and elected to take off in weather conditions
that not only suggested but also should have red-flagged, even to a pilot
far less experienced than Captain Morwood, the possibility of snow- and
ice-contaminated wings, clearly indicated to me either an incomprehensible
and deliberate disregard by the flight crew of these obviously
dangerous conditions or, more probably, a failure to appreciate fully the
adverse effects of the cold-soaking phenomenon and the problems of
performance degradation caused on takeoff by contaminated lifting
surfaces. These problems are discussed elsewhere in this chapter.


p. 302 Part Four: Aircraft Investigation Process and Analysis

and,

"It must be stressed, in the strongest terms possible, that neither the
performance subgroup nor this Commission advocates the use of
non-standard handling techniques to operate aircraft in adverse weather
conditions as an alternative to the proper preparation of the aircraft for
flight ."

p. 342 Part Four: Aircraft Investigation Process and Analysis


I think since Dryden, matters have changed and crews know more about "performance" in this sense. Also, Moshansky is extremely critical of the Fokker contaminated runway takeoff performance data and states that the existence at Air Ontario of "alternate" tables (from Piedmont and US Air) does not resolve the issue but confuses it because there was no guidance on which tables to use, and the Fokker tables were far less restrtictive but very confusing. But Moshansky is quick to point out the same point I was making in the earlier response...that "knowing" does not mean that there is an alternative to "proper preparation for flight", which I take to mean using the FCOM and following SOPs including performance numbers.

All this is in Volume 2, around pp. 302 to about 371 or so. It still makes for difficult reading, all considered.

Does this clarify things DEFCON? I'd be interested in hearing if there is still a difference in views.

Don

Edited by Don Hudson, 19 February 2012 - 03:54 PM.

[DEFCON]

You’re very thorough Don and with one exception, we’re clearly on the same page.

I’m not sure, the format / style of today’s initial & recurrent ground-schools (push the ‘on screen’ buttons until you get the correct answer) is improving the pilots ‘base of knowledge’? From my pov, it appears the new style training seeks to improve efficiency & is intended to streamline training and produce a ‘candidate pilot’ on budget?

A portion of my position comes about as a result of experiences such as the following. Approximately seven or eight years ago, I had occasion to board a flight and occupy the jump seat on a type new to me. During the flight I had quite a few questions respecting the aircraft and its ‘general’ performance. Being, the Cpt. was the FP, most of my queries were directed to the FO. When we got into T/O performance issues, the FO, not knowing me from Adam, turned to me and suggested jokingly, because I obviously knew more about the ac than him, I should take his recurrent for him the following week? He had two years on type?

The Captain just gave me the ‘look’. After landing, the Captain & I spoke on the bridge. He told me this FO was in fact one of the better ones. He went on to suggest most really didn’t have much of a clue because they had moved up through their new careers at a pace which exceeded their experience and understanding?

[Dork]

There will be lots of active discussions like these over the next 5 to 10 years or so once the rash of Low Wage Carriers come to fruition.

Perhaps old fashioned pilots who have test pilot experience, multiple APTL's and air demontration experience will then be more appreciated later on in North America.

At the moment only China seems to appreciate and understand that..or at least the aviation insurance industry does.

Lessons forgotten or ignored have to be learned again.

Dork

Per Ardua...Cumulo Granitus

[Don Hudson]

DEFCON, I suspect we agree even on that.

Re "He told me this FO was in fact one of the better ones. He went on to suggest most really didn’t have much of a clue because they had moved up through their new careers at a pace which exceeded their experience and understanding?", and Dork, re, "There will be lots of active discussions like these over the next 5 to 10 years or so once the rash of Low Wage Carriers come to fruition."

The airline industry itself...not necessarily the operations people (although operations people still aren't safety people), but the financial people, executive leaders who know more about marketing than they do about aviation, and the shareholders have created the circumstances which are slowly resulting in the destruction of standards and professionalism among its aircrews.

Some say that paying a pilot more will not make him or her safer. I agree - that ship has sailed. The key is in making the career attractive to young people so those who will make fine pilots will choose the profession.

You cannot pay a professional airline pilot $16,000 (the Colgan F/O) to $35,000 per year while removing all incentives which normally bring people into the profession, and expect to draw qualified, keen and eager candidates. Your story, DEFCON illustrates perfectly what is meant by this.

It doesn't take much to fly an airplane. September 11th tragically proved that. The mistake is in thinking that a professional pilots' job is to do just that..."fly" the airplane, and nothing could be further from the truth. Saying that is like saying the surgeon's job is to use a scalpel to cut skin and muscle in an operation, or a lawyer's job is to argue before a judge and jury in court or the dentist's job is to drill teeth.

Whether it is the tyranny of the quarterly report or the punishment shareholders offer up to a company which must plan years in advance, not days or months, the outcomes are the same - the inability to charge sufficiently for services rendered, due to false expectations brought about by the deregulation experiment. The first and increasingly the only place from which blood may still be extracted is from employees, because the oil companys, the banks and even the shareholders are in no mood to give. And I don't believe we have hit bottom yet in terms of how low pilot wages can go before passengers themselves recognize that things have changed.

Professional competency is as much about knowing what one doesn't know about one's field as it is judiciously applying what one does know while seeking answers and continuously learning from others. The F/O you mention seems comfortably numb and seems to have permitted others to dictate his level of professionalism. If he was truly as you describe, he should be much better, and should be ashamed of himself to respond as he did. As always, we can fly comfortably for thousands of hours until in one minute we can't.

At the same time, some people simply don't belong in the cockpit of an airliner, and some people don't even belong in an airplane. But, as the pipeline dries up for reasons which should now be well understood, such people, good persons though they may be, are going to end up in places they may very well be unqualified for. Shortened, cheapened training will only exacerbate the problem.

Don

Edited by Don Hudson, 20 February 2012 - 07:28 PM.

[DEFCON]

Well written!

[Don Hudson]

Thanks DEFCON...a lot of observers are seeing these trends. I'm not averse to change in terms of addressing challenges other than the safety of the industry...thank heaven for change! I am averse to an approach that is slowly fostering competence issues through wrong assumptions, undervalued skill levels, over-reliance on microprocessors and complex solutions in software and the challenge of showing profit while keeping the other two legs of the 3-legged stool fastened on! Humans are unbelievably creative in problem solving and I probably just can't see where the imaginative solutions to these issues is going to come from, but come they will !

Don