Boeing 737 NG and classic questions

[FlyingStone]

Originally Posted by downwind

In the engines introduction section of the respective FCOM's on the classic and NG, Boeing recommend the below techniques for overboost, however I cannot find reference to this in the QRH maneuverer section and or FCTM???

B737 Classic FCOM

“With the PMCs ON or OFF, advancing the thrust levers full forward provides some overboost and should be considered only during emergency situations when all other available actions have been taken and terrain contact is imminent.”

B737NG FCOM

“If the EECs are in the alternate mode, advancing the thrust levers full forward provides some overboost and should be considered only during emergency situations when all other available actions have been taken and terrain contact is imminent.”
Question.

It seems rather imaginative from Boeing to suggest this under a extreme high pressure situation this action "only during emergency situations when all other available actions have been taken and terrain contact is imminent" also to add the PM would be looking at the overhead panel rather than supporting the PF in their efforts to avoid the terrain?

Based on the above FCOM statements why would Boeing mention this, after having performed this in the B737NG sim for a bit validation it seems rather crazy this recommendation and contrary to QRH maneuverer section and FCTM. Please note this technique/procedure seems more relevant to the B737NG due to the EEC’s.

First of all, nowhere does Boeing say you have to look at overhead panel during the manuever itself. You should be aware whether you are operating with PMC OFF or EEC in ALTN mode as:

1. There is a master caution indication, after which you will either perform QRH actions or if on the ground, dispatch the aircraft in accordance with MEL/DDG.
2. If this is the case, I imagine both of the pilots will be VERY aware that they are operating the aircraft in a non-normal configuration and some normal and non-normal procedures must be adjusted to account for the previous failure, as Boeing QRH only takes single failure into account.

Second, every single B737NG QRH I have seen contains this note under the Manuevers section (for both Terrain and Windshear escape maneuvers), which I believe is quite self-explanatory:

Note: *Maximum thrust can be obtained by advancing the thrust levers full forward if the EECs are in the normal mode. If terrain contact is imminent, advance thrust levers full forward.

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Additionally, the B737NG FCTM also provides similar guidance in the "Maximum thrust" section:

The term “maximum thrust” is used in various places in the FCTM and the
FCOM. Maximum thrust is attained:
• for airplanes with electronic engine controls (EECs) operating in the
normal mode, by advancing the thrust levers full forward
• for airplanes with EECs operating in the alternate mode, by advancing
the thrust levers to the full rated takeoff or go-around limit only.
Advancing the thrust levers to the full forward stop should only be
considered if terrain contact is imminent.

Third, on the B737 Classic one should never firewall the thrust lever or advance them beyond full rated thrust (TO / GA N1 limit), unless terrain contact is imminent, regardless whether the PMC is operative or not, as the engines have no protection.