Originally Posted by PukinDog
1. From the report: "The Federal Aviation Regulations are very specific, requiring that "no person may take off an aircraft when frost snow or ice is adhering to the wings, control surfaces, or propellers of the aircraft." The crew knew they had a contaminated wing with frozen precip adhering, yet they took-off it anyway.
Once again – I’ll take the time to point out that both the regulation and persons reading the regulation continually pointed to the word “adhering” with an impression of its meaning that obviously differs from yours. Clearly, you are one of those persons who believe that if snow is on a surface, that fact alone is sufficient verification for you that the snow is “adhering” – but even then you seem to have “widened” the door to allow some other possibilities to sneak through. In one of your earlier posts you said …
If its not wet and glossy but turned opaque, and especially if there's snow present on the fluid surface, the solution has lost the ability to melt frozen precip and absorb/suspend/depress the freezing point of the water. Unless other procedures have been approved in the Ops Specs, the general rule for U.S. air carriers (121.629) if HOT has been exceeded there must be pre-takeoff contamination check accomplished within 5 mins before T/O, and it must be done from outside the aircraft.
While most the above quote is accurate – you haven’t provided any information as to when this language first appeared in the section you cite … and, in a difference from your quote, the actual rule language describes that a takeoff may be made if the maximum holdover time does not exceed that found “in the certificate holder's holdover timetable” – suggesting quite strongly that differing time periods are not only acceptable, but that they do exist – even in the current environment – which, as you know, is substantially more knowledgeable in these areas than what existed 30 years ago.
I’ll also point to your description of some snow where you certainly imply it be allowed on an airplane’s surface…
In any case, no matter how you're trying to parse it, if it's not a dry, feathering snow readily sliding off a cold-soaked wing but is accumulating on it instead, then it must adhering somewhere...
I read that as saying “…if it IS a dry, feathering snow that is readily sliding off a cold-soaked wing … then THAT snow would be allowed to accumulate because it would not be “adhering”… is that what you meant?
…accumulated on de/anti-ice fluid, the fluid has failed (and) this "accumulation" of snow … doesn't meet the criteria "free of" (therefore it is considered) contaminated.
So, by your description, my question would be … just exactly how long after a snow flake falls on a surface that has had a coating of anti-ice fluid applied would that snow flake be rendered to a state of a harmless fluid? Equally important, does the rate of snow fall have any impact on this process? I’m just wondering, under your conception of the process, how it is that an airplane is allowed to takeoff during a falling snow?
Originally Posted by PukinDog
2. The Air Florida company Ops Manual mirrored that same Reg, but with relief granted for dry snow if the Captain and person releasing the aircraft agreed conditions precluded adhering. That relief was never sought, and the mod-heavy wet snowy conditions weren't of that nature anyway. So with regards to "clean wing"/contamination", there's no question the crew didn't follow their own Ops Manual either as it existed in 1982. Ignorance of his own Manual?..or disregard for it.
And
3. Inspection after de-icing. From the Report: "Neither the Air Florida maintenance representative who should have been responsible for proper accomplishment of the deicing/anti-icing operation, nor the captain of Flight 90, who was responsible for assuring that the aircraft was free from snow or ice at dispatch, verified that the aircraft was free of snow or ice contamination before pushback. Ignorance of his own Manual? or disregard for it.
You “say” that relief was never sought … you say that no one verified that the aircraft was free from snow or ice … obviously you are not aware that it was the Captain (in coordination with the company maintenance supervisor on duty ... to some degree) who was responsible for “releasing” the aircraft? According to the Accident Report (page 3) “…the same American Airlines mechanic that had inspected both engine intakes upon completion of the deicing/anti-icing operation performed another general examination of both engines. He stated that he saw no ice or snow at that time. Air Florida and American Airlines Personnel standing near the aircraft … stated that they did not see any water, slush, snow, or ice on the wings.”
Originally Posted by PukinDog
4. Use of reversers. The Air Florida Ops Manual at that time also included Bulletins warning of possible clear ice formation on leading edge devices while using reversers on the ground with snow present. There were also a series of Bulletins and avisories regarding rotation/pitch and roll issues with contamination on the leading edges, and recommended procedures for takeoffs into icing conditions or where contamination may be present. The Captain used the reversers for 30 to 90 seconds at the gate, after de-icing. Ignorance of his own Manual? or disregard for it.
And you admonish me for “cherrypicking?” Come on, sir … let’s be fair. While it is correct that the Ops Manuals very likely discussed the kinds of things you say – did you possibly check to see where in the manual such statements were made. For example, in discussing the arrival of a flight into a terminal area during snow conditions, that same manual said the following – also quoted from the Accident Report:
A buildup of ice on the leading edge devices may occur during ground operations involving use of reversers in light snow conditions. Snow is melted by the deflected engine gases and may refreeze as clear_ ice upon contact with cold leading edge devices. This buildup, which is difficult to see, occurs in temperature conditions at or moderately below freezing. Crosswind conditions can cause the ice buildup to be asymmetrical, resulting in a tendency to roll at higher angles of attack during subsequent takeoffs.
I’m sure you know of the problems that may be caused by landing on a snow-covered runway, stopping with the use of up to and possibly including full reverse thrust (which as you know throws anything on the ground – like water or snow – forward of the airplane and likely impinges on that airplane as it moves forward. Additionally, taxiing in to the gate after landing, a flight crew may well use reverse thrust to assist braking effectiveness. The quote you provided is almost always read in the context of a “between approach – through the landing – taxi in – and parking sequence.” This why the quote you provided clearly describes problems that may be encountered with “subsequent takeoffs.”
In your incessant arguments that this situation was complicated by a couple of bafoons to knew little and cared less. You continue to cite what you believe was a deliberate maneuvering of their aircraft to be “deiced” by the jet blast of a preceding airplane. I hope to goodness that you are never recorded, in a moment of utter frustration, uttering a hyperbole (such as “I’d sell my oldest child for a parking place!) because someone with your penchant for not understanding the potential uses of such parts of speech in, at least the Americanized version of, the English language is going to think you more than just a bit nuts – when those of us here have come to recognize that you are certainly not nuts.
While we are looking more carefully at the contents of that company’s Ops Manual, it might interest you know that the following was contained in that manual as well – as prescribed by the airplane manufacturer (again, from the Accident Report, page 37)
Section 3A-7, page 2, of the August 20, 1973, issue of the B-737 Operations Manual, Supplementary Procedures, Ice and Rain Protection, “Wing Anti-ice,” states: There are two methods recommended for operating the anti-icing. The primary method is to use it as a deicer, by allowing the ice to accumulate before turning it on. This procedure will provide the cleanest airfoil surface, the least possible runback ice formation, and the least thrust and fuel penalty. Normally, it will not be necessary to shed ice periodically unless extended flight through icing conditions is necessary (holding). Ice less than 3 inches thick will have little effect on airplane handling, therefore, the ice accumulation may be allowed until the icing condition has been passed. The secondary method is to turn the wing anti-ice switch on when wing icing is possible and use the system as an anti-icer.
I’ll just leave that manual paragraph alone for anyone’s contemplation.
You can – and you have – criticized these crewmembers quite heavily – they and their families paid – quite heavily for any mistakes they may have made – certainly relying on what and how they were trained, relying on a competent ground crew to deice and anti-ice their plane – doing what everyone else that day appeared to be doing – wasn’t all a mistake.
Do I have an agenda? You bet. And I thought I made that perfectly clear in my first post on this thread. The reason I interjected my original comment into this thread was not to start an unwanted argument about what should have been done or what the flight crew should have known and did know. My original comment was to correct what I saw as an incorrect impression that it was a the low engine takeoff power that caused the accident. The NTSB officially, and at least one NTSB participant (quoted by one of the posters here) collectively agreed that the engine power setting did not cause that accident. The NTSB reached the conclusions they reached. Some of us in the aviation world disagree with those conclusions … welcome to the world of individuality. There will inevitably be doubts and incomplete knowledge in almost any accident scenario … and I sincerely believe THAT is the primary reason that the NTSB does not publish “Accident Causes.” They publish “Probable Causes” of accidents. Do I expect the conclusions reached in this accident to be changed? …not hardly! Does that mean I agree with all that was said in that report? …again, not hardly!
One thing I hope I am never caught doing is besmirching the reputation of fellow aviators that have experienced unfortunate turns of events. I’ll leave the allegations of “lack of awareness;” of “providing Laissez faire ‘non-answers’ to questions;” and the like to others. I would hope that any professional on this or any other forum, or in any other exchange of philosophy or ideas or questions, will examine all there is to examine – including the concerns, opinions, and beliefs of others – not to the exclusion of facts, but perhaps to bring slightly differing highlights to those facts … to better understand and appreciate what happened …and then do all they can to learn from what those actions have provided.