PPRuNe Forums - View Single Post - Using GPS ground speed to resolve Unreliable Airspeed
Old 4th Jun 2019, 11:26
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yanrair
 
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Originally Posted by Bergerie1
yanrair,

At one time in my career I also used to sit behind that 'green table' but mine was an old wooden desk. I had the same attitude as you about learning from experience and helping people in their jobs. The most important thing was to analyse what had happened and then publish what had been learnt. Some while ago I wrote a note on the slavish adherance to SOPs. I quote the final few paragraphs here:-

"However, despite all these considerations, it is impossible for the SOPs to cover every eventuality. There then comes the point when they are not appropriate to the situation and the captain decides to deviate from them. This is an extreme measure and should only be done when there is no other option and when the pilot has sufficient knowledge to understand fully the implications of what he is doing. I can think of several examples.

Suppose on take-off at maximum weight in a four engine aircraft (a 747 with multiple landing gears) at a hot and high airfield, birds are ingested into both engines on the same side. Then, when airborne only a few feet above the ground, and barely able to climb, the co-pilot calls positive rate of climb, but the captain elects to leave the gear down until more speed and altitude has been gained. Non-standard, but his reasoning is that the extra drag of the open doors and wheel wells will probably cause the aircraft to sink back towards the ground.

Suppose on final approach all engines suddenly stop. The captain elects to retract the flaps one notch. Non-standard, but the drag reduction is just sufficient to stretch the glide and make the airfield.

Suppose in mid-Atlantic, the underfloor cargo fire warning lights illuminate, the crew have reason to believe the warning is genuine and divert to the Azores. When they arrive the weather has deteriorated, the cross-wind has risen above limits and the cloud base has descended to below decision altitude. There is nowhere else to go and it is imperative to land. They do so successfully. All three examples were genuine events. It is not difficult to dream up other scenarios where such actions may be necessary.

And one more to ponder: the Qantas Airbus A380 at Singapore when a turbine disc exploded causing extensive damage and multiple unrelated warnings. In what order should the crew action the various procedures, which should be ignored and which have to be actioned?

My conclusion, therefore, is that normally flight crews should always obey the SOPs, even in an emergency, yet there may still be times when circumstances may dictate otherwise. Then, and only then, is it permissible and maybe essential to deviate, but this must be done in the full knowledge of ALL the implications. SOPs are for the guidance of wise men and not necessarily to be slavishly followed."


Not all flight managers act in the draconian manner that some posters here on Proone seem to think!
Dear Bergerie
Looks like we went the same college of airmanship.
I could add many more to that list - a lot of folk think that every time the manufacturer must have thought out a solution and it is in the good book. But no. Boeing make great planes but I always used to say, "they don't know how to fly them in an airline environment." And they don't even try. A Boeing FCOM 1 (user handbook if you own a washing machine) barely scratches the surface of how to operate an airliner.
Take 767 engine fail at 30W mid Atlantic. QRH says descend to drift down altitude. (FL 330) and set up MCT. It happened to one of my guys. He did nothing of the sort , arguing that that to sit there at MCT on the remaining engine was inviting a second failure. So, he descended to FL 200 and flew along at a nice low power setting - way below MCT to Gander where he landed with no drama and without having gunned his remaining engine for 2 and a half hours. Why do Boeing not say this? For the reason that you state - it is beyond the scope of the QRH and of course you might, just might need that extra altitude to give you extra range if your diversion field is at ultimate distance. But with Gander so close this didn't matter. And so airmanship kicked in. Funny old archaic thing that used to be prevalent.
Y
Cheers
John
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