B737NG 15degrees AofB
Joined: Apr 2010
Posts: 1,320
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From: IRS NAV ONLY
Ask him to read ICAO Doc. 8168 carefully and to tell you at which bank angle are all IFR procedures calculated. He might be quite surprised. On top of that, it only affects HDG SEL and VOR/LOC modes, so the autopilot will still bank up to 30° AOB in cruise while in LNAV.
Joined: Mar 2001
Posts: 4,563
Likes: 35
From: I wouldn't know.
Isn't there an "Auto" position??
Joined: Jun 2008
Posts: 4
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From: Spain
The limitation does only apply if you are using HDG SEL during an Engine Failure or during the Cruise close to the Opt/Max Altitude. LNAV is AoB protected tough and will use whatever it needs even if you have it in 15 degrees AoB
It is a protection that couples with the F/D as part of the AFDS.
Hope you find it useful
It is a protection that couples with the F/D as part of the AFDS.
Hope you find it useful
Last edited by olmedo; 27th November 2015 at 15:01.
Thread Starter
Joined: Oct 1999
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Yes I understand all of that. They set it on departure just in case they get engine failure and need for emergency turn. But they leave it at 15 all the time.
I convinced that all sids and stars with headings are all worthless now.
Just need a reference to show him that he is wrong.
I convinced that all sids and stars with headings are all worthless now.
Just need a reference to show him that he is wrong.
Joined: Apr 2010
Posts: 1,320
Likes: 102
From: IRS NAV ONLY
Nope, it will use automatic adjustment of AoB in LNAV and VORLOC, but in HDG it will use the AoB selector setting
Just need a reference to show him that he is wrong.
Joined: Sep 2014
Posts: 116
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From: Someone else's acft
FlyingStone... And you were right.
The Bank Angle Selector DOES affect the VOR/LOC mode. Try capturing the localizer with the bank set to 10 degrees and see what happens.
(But don't try it somewhere with parallel runways, just a friendly advice)
The Bank Angle Selector DOES affect the VOR/LOC mode. Try capturing the localizer with the bank set to 10 degrees and see what happens.
(But don't try it somewhere with parallel runways, just a friendly advice)
Joined: Jun 2000
Aviation Qualifications: ATP+Mil
Posts: 4,698
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From: Australia
My colleague has it selected for the whole flight. Take off, cruise and approach.
The statistical chances of having an engine failure on take off at the exact position where a curved take off starts and at a speed where you need exactly 15 degrees angle of bank, are so small that you could go through your entire career without it happening. And to have the selector set to 15 degrees in all stages of flight is nothing short of puerile thinking. Superfluous SOP's are the bane of this industry.
If it does happen while your angle of bank limiter is set to the normal 25 degrees, it takes less than a second for the selection to be made to 15 degrees if you are unable to operate without the aid of a FD.
Joined: Jun 2000
Posts: 4,507
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From: last time I looked I was still here.
PinHead: Ask your colleague to explain his reasoning behind this selection. Consider it and then come back here and tell us. Then we can make informed judgements and advise you.
