Re: auto-throttle usage

From: (Jos Gielen)
Organization: Euronet Internet
Date:         05 Sep 95 01:59:58 
References:   1
Next article
View raw article
  or MIME structure

Airam J Preto <> wrote:

>Last week, a T.V. documentary showed a take-off exercise using what
>seemed to be a B-767 simulator. As the airplane was rolling gaining
>speed one member of the crew said "auto-throttle engaged!". I'm curious
>about that.

>Which is the standard procedure during:

> - Take-off (auto-throttle engaged?)
> - Altitude and speed transitions (auto-throttle + autopilot?);
> - Approach and landing (autopilot and then auto-landing?).

"Standard"  procedure differs widely. As a rule you can say that
Take-offs are made with auto-throttle (A/T) on and autopilot (A/P)
off. That is, on "modern"airplanes.
Somewhere after take-off the A/P is engaged. As a pilot you're usually
free to do so whenever you feel like it, or when it seems
operationally beneficially. There are different minimum heights for
A/P engagement per aircraft type however. (typically around 500 ft)

Climb, cruise, descent and initial approach are normally flown with
A/P and A/T engaged.
Whether a landing is performed as an autoland depend on ground
equipment and weather. If its going to be an autoland, its also A/T
Manual approaches can be flown with either A/T on or off. On aircraft
like the B767 or B737, with underslung engines the A/T can be a real
nuisance during manual approaches, due to the pitching moment the
underslung engines create. An MD11 however doesn't have that 'pitching
moment due to its tail mounted engine nr 2. It can comfortably be
flown with the A/T on until touchdown. The A/T takes care of automatic
thrust lever retardation upon the flare manouvre.

Apart from unsuitable ground equipment, manual approaches are
typically flown in good weather conditions (in an European context
this would be more than a mile visibility and more than 300 ft
ceiling) or with strong and gusty wind. Apart from reduced visibility,
autopilots are still less capable than human pilots, despite what
Airbus says.

Hope this answers some of your questions.

It's hard to soar like an eagle
when you have to fly with turkeys