Boeing 737 classic/Ng question

[downwind]

Hi all

Assuming you conduct a bleeds off takeoff and suffer a eng fire/engine failure etc.... after the engine fire/fail nnc memory/ read and do steps have been done as the case may be and the engine out acceleration altitude is reached, as per fcom supp procedures, do you need to reconfigure the bleeds to on? If you intend to return to the departure aerodrome?

What are people's opnion of this, or is the boeing qrh eng fire Nnc engine failure nnc assuming either a bleeds off or on takeoff (from my personal observation) and the qrh checklist steps take care of the pneumatic switching

I was looking in the fcom/qrh to try and see what boeing's stance on this was, I cannot seem to find a reference from the manuals?

Second query:

Does The pps best hold speed on the fmc take turbulence into account? For low altitude holding or slowing up due to act sequencing?

Thank you and happy new year.

[FlyingStone]

Boeing only produces NNCs for normal aircraft configuration, in this case Bleeds ON takeoff. You have to use either common sense when you get to the isolation valve/pack/engine bleed step in the NNC or combine the NNC and the after takeoff part of the supplementary procedure.

As for the hold speed, as long as you are at or above flaps manuevering speed, you can make turns with 25° (+ 15° overbank margin) of bank. And as long as you are at or below turbulent air penetration speed, you are in the optimum range as far as the turbulence goes. The Bill Bulfer's 737 FMC guide says the "best speed" on hold page is higher of minimum fuel flow (max endurance), minimum manuever or initial buffet speed.

[ImbracableCrunk]

The turbulence speed is not an upper limit, it's the target for severe turbulence. Yes, in theory you might need to speed up.

[framer]

As for the hold speed, as long as you are at or above flaps manuevering speed, you can make turns with 25° (+ 15° overbank margin) of bank.

Probably a good idea to be a bit conservative about the above bank angles if you are at altitude and the FMC hold speed. Chances are you won't be able to maintain both at the same time.

[ClimbSequence]

Our company SOP's follows a priority sequence to run the checklist/steps. The acronym MENCAS help us to remind it and it is perform as follow:
- Memory or recall items
- Emergency checklist
- Normal checklist
- Circuit Breakers
- Abnormal checklist
- Supplementary (if applicable)

So eventually there will be a point during this pattern in which you will reconfigure the remaining pack/bleed available to ON

[B737900er]

The supp Procedure for a Bleeds off take off states, if an engine fails reconfigure the bleeds above minimum 1500AGL.

[Tee Emm]

Circuit Breakers??

It is a potentially dangerous policy to reset popped circuit breakers unless urgently required for operational reasons. Therefore what is the point in having "Circuit breakers" in the mnemonic? It serves no useful purpose unless called for in the manufacturer's QRH

[despegue]

Tee Emm,

Always check the breakers, it is good airmanship.

Mind you, I am not writing RESET the breakers, but when time allows, check which breakers have popped to get you a better overall idea of the actual situation.
Check LIST
Check Breakers
In that order.

Don't do this in the sim where I fly and you will get a reprimand for sure and for good reason.

[kwstas]

Hi, Supplementary procedures states,"If engine failure occurs, do not position engine BLEED air switches ON until reaching 1500 feet or until obstacle clearance height has been attained."
So IMHO states what you have to do until 1500 ft, above that height it is in flight crew discretion. My personal opinion is that if the aircraft will be returned to T/O airport I would't bother reconfiguring DCPCS. As it was said by FlyingStone Boeing assumes normal configuration before performing a QRH checklist.