757/767 Autopilot Performance Limits?
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Joined: Jul 2008
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From: Las Vegas, NV
757/767 Autopilot Performance Limits?
Was hoping to learn what the minimum altitude and/or maximum air speed operation limits may be, for 757 and 767 model aircraft in autopilot mode. (If any).
Was also interested in knowing if there are limits to the rate of ascent or descent of a 757 and 767 in autopilot mode.
Was also interested in knowing if there are limits to the rate of ascent or descent of a 757 and 767 in autopilot mode.
Last edited by Badmachine; 11th July 2008 at 07:31.
Joined: Feb 2003
Posts: 1,078
Likes: 46
From: Brighton
It's a few years ago, but this is what I can remember..............
First, the flight director and autopilot are integrated in that they have common controls and (mostly) common modes - the A/P does not have a take-off mode.
Minimum altitude:
On take-off, the SOP of the company I flew for was not to engage A/P until after clean-up, about 1000ft aal, and VNAV had been selected. Reason for that was if you selected A/P with the F/D in take-off mode, the vertical mode changed to vertical speed, which was not a good idea. The Boeing Flight Crew Training Manual states the A/P is certified by the FAA for engagement at 200 ft aal.
On landing, there is an autoland capability, which with an approved ILS will provide guidance throughout the landing and rollout. You have to disengage to turn off the runway, though......................
For a non-precision approach, the modes used are heading select and vertical speed; the minimum height for A/P is a few hundred feet, though I don't recall the exact figure.
Max speed: no limit other than the airframe IAS/Mach limit.
Max climb/descent rates: limited only by aircraft performance.
Any current B757/767 driver care to correct any errors?
First, the flight director and autopilot are integrated in that they have common controls and (mostly) common modes - the A/P does not have a take-off mode.
Minimum altitude:
On take-off, the SOP of the company I flew for was not to engage A/P until after clean-up, about 1000ft aal, and VNAV had been selected. Reason for that was if you selected A/P with the F/D in take-off mode, the vertical mode changed to vertical speed, which was not a good idea. The Boeing Flight Crew Training Manual states the A/P is certified by the FAA for engagement at 200 ft aal.
On landing, there is an autoland capability, which with an approved ILS will provide guidance throughout the landing and rollout. You have to disengage to turn off the runway, though......................
For a non-precision approach, the modes used are heading select and vertical speed; the minimum height for A/P is a few hundred feet, though I don't recall the exact figure.
Max speed: no limit other than the airframe IAS/Mach limit.
Max climb/descent rates: limited only by aircraft performance.
Any current B757/767 driver care to correct any errors?
Last edited by kenparry; 12th July 2008 at 07:08. Reason: expanded approach detail
Joined: Sep 2003
Aviation Qualifications: ATPL
Posts: 956
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From: away from home
From the B757 & 767 FCOM Limitations:
After takeoff, the autopilot must not be engaged below 200 feet AGL.
Thats about it.
After takeoff, the autopilot must not be engaged below 200 feet AGL.
Thats about it.
Last edited by oceancrosser; 11th July 2008 at 23:51.
Joined: Sep 2007
Posts: 388
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From: uk
pretty much as ken says with additional approach limits of 180' AGL on single channel ILS and 300' agl on non-precision approach ( a few B757s had/have selectable single or multi-autopilots e.g. BA and Air Europe whereas most have multi-autopilots " automatically" on an ILS. Identified by by paddle switches or push buttons respectively and the latter cannot select single channel ILS except following failures)
