Use of autothrust on approach, B757/B767

[Richard Spandit]

Just completed a line check with an airline I won't mention. Was given a black mark for disconnecting the A/T at the same time as the A/P on the approach. Their SOP is to leave the A/T engage until the flare - I was taught that flying manually but with autothrust could lead to unnecessary oscillations - something perhaps the Airbus compensates for (I have been told that Airbus pilots rarely disconnect the A/T - if this isn't true, let me know)?

Any useful comments?

[763 jock]

You did right. The autothrottle should have been disconnected at the same time as the autopilot. If you ae planning a manual landing, the crew are responsible for the gust factor additive. Autolands require Vref+5 and the autothrottle does the rest. Where is your airline based?

[Guzzler]

Just completed a line check with an airline I won't mention.

Our Canadian brothers forbid the use of manual thrust on the Airbus unless the Auto-thrust is U/S.

With our own company the use of manual thrust is down to pilots preference and IME I would estimate manual thrust is used on about a third of manually flown approaches.

[t-bag]

Got my black pen out if you leave it in when you come home! Cant win huh ! 763 jock is right, it should be out .

[scanscanscan]

Had this one in GF......solved by what the Boeing training manual said.

[Richard Spandit]

Had this one in GF......solved by what the Boeing training manual said.

Which was?

[757manipulator]

"To simplify thrust setting procedures, 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 autopilot is engaged"

ref: 757/767 Flight Crew Training Manual/General information 1.28

October 2003

[Richard Spandit]

I thought that was the case - obviously the airline refuses to let go of its Airbus past and fully embrace the Boeings they have. I think I'll disregard their policy and fly the way I always have done...

...no comments please!! :)

[Right Way Up]

Our Canadian brothers forbid the use of manual thrust on the Airbus unless the Auto-thrust is U/S
If an airline plays this line I would be inclined to refuse an aircraft with autothrust u/s. They cannot have their cake and eat it.

[Charles Darwin]

Quite right there lad!

[PRNAV1]

bit odd...manual throttle i say but like sum1 said, what do boeing recommend..?

[757manipulator]

Just to reiterate what Boeing say....
"To simplify thrust setting procedures, 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 autopilot is engaged"
ref: 757/767 Flight Crew Training Manual/General information 1.28
October 2003
Straight out of the Boeing FCTM as above

[Guzzler]

Just to reiterate what Boeing say....
Straight out of the Boeing FCTM as above

ie doh!

:)

[xdc9er]

Boeing " reccomends", ........use your SOPS backed up by the AFM, mixed with a little experience,.....
X
Thats like "shall and "should", two very different meanings , not open to interpretation.

[fadaknet]

I'm sorry :{:{:{

[PW1830]

The Boeing FCTM does recommend manual thrust when A/P disconnected -have not been able to find a valid reason for this apart from the Air France accident in PPT 10? years ago.A contributing factor was A/T use when flying in VNAV. At the MAP, the A/T transitioned to GA mode and a disconnect at that time would have been appropriate. From memory one of the recommendations was that this feature be advised to pilots - never happened. Instead we get the disconnect recommendation.
As the VNAV approach is now programmed on our 767/744,this will not happen - A/T maintains CAC speed.
The A/T used with manual flight works extremely well - if you don't like it disconnect it - the usual disclaimer.
I have used it for 20 years on 767/744 eg excellent for the old HKG and Carnarsie New York 13 approaches and have suggested my students do the same.

[Jonty]

The reason given to me, as to why we don't use it on the B757 is that of PIO. The pitch up couple on the 757 is very noticeable and the pilot can soon get into problems if he does not know what the A/T is doing. Especially if it whacks on, or removes a load of thrust in the late stages of the approach. We tend to use it in the take off and climb, but then the thrust doesn't change much until Alt Cap.

[PW1830]

PIO will certainly induce A/T activity.
Soon learn to minimise the PIO!

[BlueEagle]

A company I worked for stated in the Ops Manual that never use Autopilot without A/T but that A/T without Autopilot was permissible at pilots discretion but had to be disconnected before touchdown. The approach into HKG on a dirty wet night was always interesting so keeping the A/T in until just around the corner could be a help if it didn't 'hunt' too much, I found.

Regarding the PPT accident I was under the impression that the lady co-pilot flying the approach did keep the A/T in and on touch down went to select reverse but missed a reverser or two, (possibly due to small hands), so as she pulled what she had in her hand back the 'loose' one moved forward and they swung sideways off the R/W, but that is only what I heard at the time.

.

[superpilut]

Yeah, but can't it be they want you to leave the A/T armed?

Like when you are on final approach, you can of course push the N1 or Speed button (whichever mode you were in) , so you will keep envelope protection or "Minimum Speed Reversion" as Boeing calls it.
So your FMA will indicate "ARM", you can fly manual with manual inputs, but as soon as you will enter an underspeed condition the Autothrottle will kick in and advance the Thrustlevers.

We had guys coming from the Lufthansa school aplying this as a standard procedure.

..sorry all, just saw I answered according 737. Didn't properly read the topic title!!!.....

[Otterman]

At my airline either is fine. Most guys click off the autopilot and autothrottle at the same time. But you can fly manually with the autothrottle engaged (manual crew coordination procedures apply). For the wind correction factor you can apply Vref + 5 if you plan on disengaging the autothrottle at 50 ft. agl (As long as there is no performance decreasing windshear reported).

With the autothrottle OFF the Wind correction Factor is ½ headwind + full gust value (min. of 5 kts, max. of 20 kts). So in windy conditions and runway length being a factor, it represents an advantage in flying with the autopilot off (in case of non-precision approach) and the autothrottle on. In these conditions it is true that you have to be right on the ball to catch the excesses in the a/t system, as pitch moment can be quite impressive. In my experience it is quite manageable. When both engines are running and no snags on the autothrottle the a/t arm switch always stays ON. For speed protection and for the thrust setting on the go-around.

Also in the thread it was mentioned that autopilot can only be used in conjunction with autothrottle. We are CAT I autoland with two or one engine operating with a/t u/s (and with only one running we have the autothrottle arm switch in OFF). And just flew a flight with the TMC u/s, and TMSP auto mode u/s. So manual thrust from beginning to end (was only a ten hour flight). It is still just an airplane.

Nonetheless it is always interesting to see what all comes out of the basic document that Boeing supplies and what our own pilot engineers in the flight technical, and training departments come up with.

Regards, O.

[junior_man]

Have flown the 757, 767 and 737 w/o autopilot but with A/T on. You do have to understand the pitch changes with thrust. Would advise not using it when you were new on the airplane.

It was pilot preference as to which way you do it at my current operator on the Boeings. Airbus A/T required and can't dispatch without it.

They were recommending leaving it Armed if you disconnected it. This was mentioned in a previous post. As well as speed protection, it also will give you autothrottles in the go around as well.