engines start 747-8 vs 747-400

[maca11 2]

Hi all, I cannot start engines in 747-8 after pushback just on APU (I can do only at stand with connected also air unit..).... whilst I can do with 747-400 (after push back just on APU)... is there a difference or it is some installation fault..?

many thanks !

[Samany69 41]

Hi Jan. 

While I haven't got the 747-8 yet, please make sure that you have APU Bleed on ! the GE-nX engines on 747-8 are not same as Dreamliner, they still start with an Air starter unit

Sincerely Yours.

[BIGSKY 316]

Packs 2&3 off?

[Samany69 41]

Just now, BIGSKY said:

Packs 2&3 off?

they can reduce the Duct Pressure but as the 747 is equipped with enough PRSOV's , they are not necessary. APU bleed is the source. 

[BIGSKY 316]

To start 2 at a time,it may be necessary to turn off all 3 packs.

[BIGSKY 316]

NP.21.32 IN -8 FCOM

[Samany69 41]

ofc, yet what he is asking is that they are not starting at all. so I assume that it is the source of pressure not the consumers.

[downscc 1,327]

Nobody has mentioned the fuel cutoff switches yet.  Pull the start button and flip up the fuel switch.  You should be rewarded with "AUTOSTART" appearing above each engine being started on the MFD engine synoptic.

[tcas_climb 45]

speaking of, how do you do a manual start in case the autostart system is inoperative?

[downscc 1,327]

If you have an abnormal start you follow the QRH.  If there is no autostart then that means there is a serious problem with EEC and you turn aircraft over to maintenance.

[Dick 47]

On the 747-8 the lights on the startbuttons on the overhead do not light up  during the engine start. That might be confusing for a 400 pilot..

Edited September 26, 2018 by dick

[thibodba57 462]

3 hours ago, tcas_climb said:

speaking of, how do you do a manual start in case the autostart system is inoperative?

No manual starts on the -8.

[thibodba57 462]

5 hours ago, BIGSKY said:

To start 2 at a time,it may be necessary to turn off all 3 packs.

All packs should be off starting one or two engines at once.

[M_Sauce 6]

There is manual starts. You use them when you have autostart faults or to motor the engine. 

Top left overhead panel, you can see the autostart switches. You can disable autostart there and then turn it into the older system. Obviously, you then no longer have protections so have to be ready to step in and abort if needed. 

[Olympic260 415]

7 minutes ago, M_Sauce said:

There is manual starts. You use them when you have autostart faults or to motor the engine. 

Top left overhead panel, you can see the autostart switches. You can disable autostart there and then turn it into the older system. Obviously, you then no longer have protections so have to be ready to step in and abort if needed. 

The engine will motor it self as needed to drop it's core temp before starting, the perks of the autostart system in the -8. These switches should be used only in case of failures of the autostart system not used in normal ops.