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B737 - Setting correct Go-Around Thrust

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B737 - Setting correct Go-Around Thrust

Old 12th Oct 2016, 13:17
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lederhosen

Thanks for your comments/observations, appreciate what you're saying about more modern times, after 27 years still believe ARM mode is the way to go and don't believe it's that hard to achieve with appropriate groundschool/SIM training.

However understand how things have changed for the "children of magenta line" generation where cutting costs necessitates a certain dumbing down where rote is more important than understanding or even more important than the "why doesn't this feel right/something's not OK" feeling that older pilots sometimes get or, equally, sometimes just some basic and simple aeronautical commonsense says "this ain't as it should be".

Certaintly ain't like the good old days!!

Cheers.
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Old 12th Oct 2016, 14:09
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I would have no problem with being told we should try and use arm more. But based on my experience I still prefer all off or all on for the 737.
I can't see the problem. The Boeing 737 FCTM advice could not be more clear. My version states: "Autothrottle use is recommended during takeoff and climb in either automatic or manual flight. During all other phases of flight, autothrottle use is recommended only when the autopilot is engaged in CMD."

Forget the why's and wherefore's. if Boeing had to provide a technical reason for all recommendations in the FCTM, the manual would be double the size.

In addition, the FCTM has this to say under Autothrottle ARM mode.

"The autothrottle ARM mode is normally not recommended because its function can be confusing. The primary feature the autothrottle ARM mode provides is minimum speed protection in the event the airplane slows to minimum maneuver speed. Other features normally associated with the autothrottle, such as gust protection is not provided."
............................................................ .....................................

Before the above advice was published, you can bet Boeing test pilots have conducted measured tests on the various autothrottle systems before final recommendations are published. Yet one wonders what causes pilots to think they know better than the experts at Boeing
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Old 12th Oct 2016, 14:39
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Certainly ain't like the good old days!!

Indeed; if thinks don't change they stay the same. Trouble is the change should be an improvement, but sadly.................

Regarding the A/T in ARM. I seem to remember this was the case on B757/767. I think those with experience of this possibility investigated/experimented and discovered it was possible on B737's. Every B737 operator I flew with, CL & NG, banned it. I see Boeing uses the phrase "not recommend". I remember an old SOP manual of mine which had a list of definitions: e.g. should not = must not = forbidden". "not recommended" = is not the normal method but is not forbidden.

So what does Boeing really mean? Denti tells us that Boeing 'approved' its use in his airline. Presumably that was at customer's request. That would suggest it is not forbidden.
In my B737CL days an RA was disconnect A/P and follow avoidance guidance. Then came NG and it's SOP, which then filtered down to CL models, was to also disconnect A/T. The reason being was to comply with the philosophy of All ON or All OFF. It was not a technical necessity, yet the 'experts at Boeing' decided it was better: not from an airmanship or technical point of view, but from a pedantic philosophy point of view. It has been discussed previously and some have said there are gotchas if you leave it in. I've also seen, in the sim, many serious gotchas after it was disconnected. Personally I preferred the earlier method. Disconnecting A/T is recommended and thus became an SOP; but it does help to understand the why's & wherefore's. But as has been mentioned elsewhere we are treated too often and too much as naughty children who should do only as we are told and not to question. However, when needs must we are supposed to act using the best solution for the unexpected scenario; except that ono-one had written that one down yet.
Agh!
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Old 12th Oct 2016, 14:58
  #24 (permalink)  
 
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Centaurus
Always enjoy your posts spoken with bags of expreience; may not always agree but certainly enjoy.

So either remove the switching outright or train pilots to understand how to use the system - not rocket science.

Simple "yes or no" answer:

"For pilots appropriately trained using the AT in ARM mode, when conditions permit, increases safety".

Yes or No??

.....awaiting all the incoming "maybes" by those who can't RTFQ or are terrified by having to think.

Cheers.
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Old 12th Oct 2016, 16:45
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Surely someone from Boeing is available to give 'the horses mouth' answer. Centaurus claims the Boeing test boys have made this 'not recommended' decision, but yet they approve some operators to do it, or some just do it anyway.
It would be useful to understand, and therefore accept or not, the blanket statement of not recommended. It would also be educational; not a bad thing in this day and age. It would give a more in-depth knowledge of how the system works and what its short-comings are. Too often we barely scratch the surface with knowledge and just do as we are told. Then some rebel decides to experiment because it seems a possibility and good idea, and the system (which ever one) bites you in the backside: and then you discover why it was a 'do not'. Unbeknown to us button pushers on the outside there were some hidden gremlins lurking on the inside that a manufacture hadn't the time to fix and so did not want them woken up.

The days when an old friend of mine was a L-1011 captain in early 80's and pilots had a semi FE training are long gone. The FE had been replaced by buttons whose systems are interconnected via strange unknown routes. QRH's have replaced trouble-shooting manuals. Pilots play the piano at their peril. The memory of a tea & biscuits moment on a B767 when the A/T would not engage on takeoff. Captain climbed out and when well out of the TMA decided to reset the A/T cb. It still didn't work, but the RAT deployed and they returned. Oops!
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Old 12th Oct 2016, 18:00
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My latest FCTM also says not 'normally' recommended, which leaves a little leeway. I have worked with Boeing approved procedures for the 737 where we pressed arm and now where we do not. Both have pros and cons, bit like Airbus Vs. Boeing, but we won't go there!
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Old 12th Oct 2016, 23:36
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Philosophy from Boeing in the good old days was:

- proper airline, able to properly train, educate and demonstrate then using the AT ARM mode no problems;

- airline unable to train properly or maybe first jet into an expanding airline etc then maybe KISS better, all completely on auto or all completely manual.

Cheers!
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