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B737 TECHNICAL QUESTIONS

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B737 TECHNICAL QUESTIONS

Old 13th Jan 2016, 12:29
  #21 (permalink)  
 
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TCAS TA only.

It is a recommendation that anytime the a/c has a significant performance degradation the TCAS should be TA only. There are a variety of scenarios which would require this. Not all are mentioned in QRH and require airmanship. In some scenarios this selection appears quite early in the QRH list of actions, good idea.
However, in Engine failure case it is No.8 and takes quite a while to reach it. In the sim I timed it at nearly 2 minutes with some slow cadets. ANC is good. QRH comers under C and thus the start of the QRH can be after some time.
In Eng Fire/SEV DAM/SEP it is No. 12. It takes an absolute age to select TA Only, all the while you have lost 50% thrust and can not follow an RA.
Worse; in Volcanic Ash = close both T.Ls and no mention of TA Only. High Oil Temp, Low Oil Pressure no mention of TA only but 1 engine is at reduced thrust.

This is very inconsistent on the one hand, and when mentioned it is far too late. Just imagine what is happening in the cockpit during a high level engine failure. High work activity with procedures and ATC. (perhaps non radar), then in the middle you get a level off or even climb RA. What are you going to do? No choice, but can you comply. Surely you need to broadcast to all a/c ASAP that you are a wounded bird and tell them to get put of the way. TA only should almost be first action. It could save your neck and many others.

How can it be that some QRHs involving lost of thrust include TA Only and other do not?
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Old 13th Jan 2016, 13:04
  #22 (permalink)  
 
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Sorry RAT5, but I disagree with you.

An RA is NOT a common occurence, and the QRH in case of engine failures or issues correctly focusses first on SECURING the Aircraft and systems.

Only then, when time permits, shall we think about secondary consequences, like TA, fuel balancing and further intentions.
It is all about priorities, and selecting TA ( and 7700 by the way while securing the aircraft) is NOT.
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Old 13th Jan 2016, 14:02
  #23 (permalink)  
 
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An RA is NOT a common occurence, and the QRH in case of engine failures or issues correctly focusses first on SECURING the Aircraft and systems.

Neither is an engine failure, but I think we shall agree to disagreed on the issue. I thought securing the a/c involved all aspects of safety and avoiding an RA which you can not comply with IMHO fits neatly into that category. The 2 seconds it takes to move one switch 1 click to avoid a whole plethora of panic in an unpredictable future seems, for a professional operator, a minute distraction. Securing the engine is not a rushed action. PF is doing the A.N. bit and PM can twiddle a little knob.
There was an occurrence at hight FL. at night, where the crew had an engine failure. They forgot the basic A.N.C. and went straight for Engine Failure procedure. Good old simulator check ride stuff. After a very very short time, while they will still trying to figure out exactly what was happening, they got the stick shaker warning. They are now in RVSM with a SE stall recovery manoeuvre. Imagine if they then received an RA restricting their descent. Who here would ignore it or try, in vain, to comply. One little knob twiddled one little click would avoid that.

I do not have stats, but I suspect there are more RA's worldwide than engine failures. All I want to do is ensure the best chance of a safe outcome.
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Old 13th Jan 2016, 16:16
  #24 (permalink)  
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Unless you are a dog owned by Pavlov then you probably won't react to an RA whilst in the middle of an engine failure.

If you blindly follow an RA without any thought then I suggest you should stay on the ground.
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Old 13th Jan 2016, 16:17
  #25 (permalink)  
 
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RAT5 if you want a good outcome just follow the QRH and company SOPs, its that simple. Don't you think Mr Boeing has already thought of that?

If you want RAT, after the memory items are completed, change the TCAS to TA only. The QRH does give the caveat of "The PIC can do any checklist off by memory if he feels that it will not jeopardise safety in doing so..."
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Old 13th Jan 2016, 23:29
  #26 (permalink)  
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Question about the

" UNCOMMANDED ROLL"

"Roll may be the result of trading edge flaps displacement due to a flap spindle fracture"

Is it possible to retract to flaps 1 in that case? Why a flaps 1 landing?


"ELEVATOR TAB VIBRATION"
"Do not deploy speedbrakes in flight" why? Increase of vibrations I guess...

"LEADING EDGE FLAPS TRANSIT"

Why is a Flaps 15 landing recommanded in that situation?
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Old 14th Jan 2016, 06:44
  #27 (permalink)  
 
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TCAS RA is not a real problem, even according to Eurocontrol bulletins, is important that you don't maneuver against the RA, if you can't comply just stay where you are; and don't forget that in many cases, during any non normal checklist the crew gives a quick shout to the atc about the problem followed by the classic "standby".

FB
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