B737-300 Thrust Mode Display

[regor]

Is there a B737-300 pilot out there who can answer me the following question. No "I think so" answers please. I need a response from someone that really knows!!

The question is:

During a non-precision approach, should the thrust mode display change from "CRZ" to "G/A" once the a/c has descended below 2000ft RA?

All answers gratefully received!!

[ 30 October 2001: Message edited by: Red Demon ]

[van Ingen]

I am a B737-800 pilot now, but before this I flew the -300 and apart from the indicating displays, the system is the same.

You seem to confuse the workings of the A/T flight mode annunciation (FMA) and the thust mode display.
This is what the Boeing Operationaions Manual says in chapter 4, automatic flight:

With the A/T Arm switch at ARM, the A/T go-around mode is armed when descending below 2000 feet RA, with or without the AFDS engaged. Once armed the go-around mode can be engaged until 2 seconds have elapsed after landing touchdown.

This reflects the A/T flight mode annunciation. During the approach MCP SPD is active and GA will be armed below 2000 feet RA.

The thrust mode display indicates the N1 limit for autothrottle and manual thrust control and is normally calculated by the FMC. On the FMC N1 LIMIT page pilot selection of thrust limits is possible, but normally N1 limits are automatically specified by the FMC.

On an ILS approach, when the GS is captured, the thrust mode display indicates GA as the N1 thrustlimit. The Operations Manual doesn't say what happens on a non-precision approach.

One my flight tomorrow I will check the thrust mode display during the approach. :)

[ 31 October 2001: Message edited by: Mach .99 ]

[ 31 October 2001: Message edited by: Mach .99 ]

[Track]

It will show GA below 2000ft regardless of AFS status. This means that on ANY approach it will revert to GA once below 2000ft.
------------------------
Track

[regor]

Thanks for the replies.

Mach .99 - The reason for my post was because the Operations manual doesn't tell me!!

Track - This is what I suspected, but have been unable to establish, until your response! Thanks again.

[van Ingen]

I checked it out in the airplane. On the ILS it will change with GS capture and on all other approaches, also manual flown with raw data (AP off, FD off) it will change below 2000 feet RA.

The manual doesn't say and Track has it right.

[Denti]

I found in my manual only two other items engaged at 2000ft RA nothing about the thrust mode display.
The A/T go-around is available below 2000ft RA if the A/T-switch is in ARM, with or without AFDS engaged.
And manual F/D go-around is available if below 2000ft RA and not in takeoff mode.
The Auto-popup feature is available below 2000ft RA as well (both F/Ds off, just hit the TOGA-button and you have a F/D guidance for go-around).
(All mentioned is for the 737-31S)

[ 04 November 2001: Message edited by: Denti ]