PPRuNe Forums - View Single Post - B747 onboard systems
View Single Post
Old 18th November 2009 | 21:38
  #25 (permalink)  
NSEU
20 Anniversary
 
Joined: Feb 2004
Posts: 1,410
Likes: 37
From: Australia
Now I'm curious, as our FCOM has very little information on this... aside from A/Throttle, EPR limit indications, LNAV/VNAV, Antiskid and left side pitot heat what else happens?
Here's the rest of the list, big and small...

LE Flap electric drive (group A), Left TAT Probe Heat, Probe Heat Engine 1 if you have RB211's, AC 1 Engine Ignition (Ignition 2 and Standby still available), Left AOA Probe Heat (remembering that these have inputs to the Stall Warning System), Left Bleed Isolation Valve can't be moved (if required to do so), Left Wing Gear Alternate (Elec Extension), CVR (on some aircraft), Center Rad Alt, Center FCC, Lower Rudder Ratio (optionally on AC Bus 2), Centre MCDU, Center MMR/ILS, 2 Landing Lights, Taxi Lights (optional), CWT Scavenge Pump, Left Ice Detector (optional), various Equip Cooling Valves/Fans and Main Forward Boost Pump #3. Further reading required, but, you will probably have problems with automatic control of one of your outflow valves... and, oh, you'll be getting lots of calls from the purser ; )
Also, remember that AC 1 is a backup for the Transfer Busses.

And, because the 28Vac Ground Service Bus is attached to AC Bus 1, you'll lose the Captain's Stab Trim indication and Brake Pressure Indication and some cockpit lights will go to fixed illumination. (no dimmer control). If you have an optional Towing Bus switch on the overhead panel, you can recover the Brake Pressure Indication by switching the Towing Bus on and turning off Standby Power (but I really don't think you'll want to do that)

Interesting mental exercise... thanks!

Rgds.
NSEU.

(EDIT) Sorry.. Missed a few...

On the AC Ground Services Bus (apart from the Battery Chargers):
Wing illumination lights, nav lights, beacons, strobes and logo Lights, Fuel Boost Pump Main Aft 2 and water system air compressor (ok if bleed air is available), U/D door power, HST pump Left, Aux Fuel Tank blower (on 744-ER), Runway Turnoff lights, Drain Mast Heaters (galley flooding possible.. cf QF incident into Bangkok) and Weight and Balance (Freighter).

(EDIT 2) Noting here that this is only AC 1, not AC & DC 1.
DC1, too, would really open up a bag of worms.

Last edited by NSEU; 19th November 2009 at 00:22.
NSEU is offline  
Reply