Mr. Doves:
I’m not going to go through the process of quoting your recent post ... so please forgive the fact that you may have to re-read your post to determine the specific points to which I’m addressing my comments ... but, I suspect you’ll probably be able to figure it out.... as I think you kindly provided “red” type for the relevant comments...
Originally Posted by Boeing Airplane Flight Manual, B-737
The B-737 engine “anti-ice” switches send a signal to the engine anti-ice valves (plural) and to the main engine control. Each anti-ice valve is electrically controlled and pressure actuated.
It shouldn’t take a rocket scientist to determine that an electrically controlled valve (taking both electrical power and pressure to open it) closes when both electrical power and engine pressure are removed - and there are very few (if any) who believe that the engines remained running providing both electrical power and engine pressure after the crash. Without power and pressure – what position would the valve resume? Right ... it would CLOSE. And, in case that isn’t clear enough, here’s a quote from the Accident Report...
Originally Posted by Accident Report, page 137
ENGINE ANTI-ICE VALVES FAIL IN THE CLOSED POSITION (AVOID ICING AREAS)
However - it wasn't the use or the non-use of engine anti-ice that caused the crash. Yes, there was ice blocking the PT2 probes ... and that caused the EPR readings to be higher than actual. But there was still 75% power being produced by both engines. That was sufficient to get the airplane to at least 150 knots - but the airplane crashed anyway. So power setting - with or without engine anti-ice - was not the cause of the accident.
Originally Posted by Doves
When the use of reverse thrust proved unsuccessful in moving the aircraft / back, the engines were shut down with the reversers deployed.
I’m not sure what point it was that you were making with this specific comment ... I am fully aware that the flight crew opened the engine reversers in an attempt to counter the forward thrust that idling engines would produce so that the smaller tug would have a better chance to push the airplane off of the gate and up the slight inclined that was present. That effort was not successful. The engines were shut down and a larger tug, equipped with tire chains was brought in to complete the push back.
Originally Posted by Doves
They underestimated the irregularity of the engines parameters for takeoff.
I am also fully aware of what was said and who said it. However, you are presuming that what the F/O said had reference to an “engine anomaly.” I’m not sure what anomaly you may think he was referencing, but the fact is that for some 20 seconds both the Captain and the F/O were apparently attempting to determine what it was that was causing the F/O to say what he said. If there was an engine anomaly, it certainly wasn’t apparent to either crew member for at least that length of time. It is my opinion (and no, I can’t prove it – but it is my opinion) that the F/O was feeling something “out of sorts” and that was the position of his hand and arm when on the throttles when the engine instrument readings were apparently indicating what they should have been indicating. Only he would have had that “feeling” and the Captain would not have noticed. Muscle memory is a very important issue when accomplishing something in a routine manner. The engines were, in fact, operating just as they should have been operating – except that the PT2 probes were blocked with ice and were producing only about 75% of the takeoff power they should have been producing. With the kind of limited visibility that existed at the time, external references would have been of little or no value to assist in judging airplane acceleration.
Originally Posted by Doves
They started the take off run 50 minutes after the de-icing.
I hope we’re not going to rehash your entire previous post ... I am fully aware of when they started their takeoff roll. And as I said the airplane immediately preceding and the airplane immediately following were both subjected to the same inclement weather that affected the accident airplane. Yet it was only the accident airplane that crashed. And, as I just pointed out to
rabski, the crash was not a 1-in-3 gamble ... the crash was caused by the ice build up on the accident airplanes wings ... put there by the deicing crew when they sprayed water all over the airplane and the engines.
Originally Posted by Doves
They began to rotate as per “the soft field” (I began to hear such an expression only since I'm instructing in general aviation) and then starting the rotation well before Vr.
As I indicated to you in my earlier response ... the F/O did NOT begin the rotation “well before Vr. The computed V-speeds (again, for your information) were V1 = 138 knots; Vr = 140 knots; and V2 = 144 knots. The CVR clearly shows the Captain calling out “Vee One.” It was 2 seconds later that the Captain said “Easy!” Again, I can’t prove it – except to note the rate of climb shown on the limited Flight Data Recording at that time – but it makes sense that this comment was a result of the airplane being rotated at an unusually high rate of rotation to an unusual and abnormally high attitude – NOT by the F/O deflecting the elevator controls, but rather because of the asymmetrical longitudinal lift that was being generated because of the ice-deformed wings – again created by the deicing crew.
If what you’re concerned about was the fact that the crew elected to depart with some accumulation of snow on the wings – I’ll agree that is just what they did. Although, being able to see the wings from the cockpit is not an easy thing to do in a B-737 – where only about the outboard 10 -12 feet are typically observable from the cockpit. If you want to criticize them for taking off with whatever snow accumulated during their taxi – you would be correct and I won’t argue ... but the same thing would have to be said for Apple 58 and Six Eight Gulf. Leaving the same question ... why would only one of those three aircraft not be able to fly? And clearly, it was the inadequate and insidious deicing process this one airplane experienced – and had nothing to do with the snow that accumulated.
Originally Posted by rabski
You can say it as many times as you like, but you will still be missing the basic point.
It doesn't matter whether you have ben de-iced with standard fluids, hot water or Bishop's Finger mixed with Baileys, as a flyer, it's YOUR responsibility to ensure surfaces are clean before aiming at the blue bit. How bloody complicated is this FFS?
Mr.
rabski
To the contrary ... I'm not missing any point. I know what happened and why. I fear it is you who fail to understand what happened. I am disappointed in that you absolutely refuse to understand the thought processes that were routine some 30 years ago – we used to think that asbestos was a good insulator – we used to think that cigarette smoking was a pleasant past-time – we used to think that 8 miles-per-gallon was reasonable mileage for a car – we used to think it appropriate for parents to send their kids to the park to play all by themselves – we used to think that taking off with a small amount of snow accumulation on a wing that had been recently deiced was OK (and there are some who STILL think that way – apparently including the various regulatory authorities). If you too wish to criticize that flight crew for taking off with some accumulation of snow on the wing ... be my guest. They did that. However, as I’ve been saying all along ... THAT was not the reason they crashed!