View Full Version : 767-300 Cross Bleed Start
Ejector
26th Nov 2005, 01:45
I recently watched a B763 in Australia during the engine start. The had one going and requested from ground ATC for "Cross Bleed Start" the got permision and then reported the engine started or somthing like that. What is this all about?
ejector
ftrplt
26th Nov 2005, 02:32
probably APU failure (no air at least).
Need to start the right with GND air cart, then start the left on crossbleed after pushback.
yachtno1
26th Nov 2005, 02:48
Might have had tower input due to running engine being above idle ...:)
barit1
26th Nov 2005, 22:03
Yep. Likely a "jet blast" (literally!) issue - to boost pneu. pressure to expedite the second start, the good capt. might nudge the throttle up a bit on the running engine.
Beware behind!
Capt Claret
27th Nov 2005, 08:36
... the good capt. might nudge the throttle up a bit on the running engine.
Are there any jet powered aircraft that can cross-bleed start without nudging the throttle up a bit on the running engine?
barit1
27th Nov 2005, 12:17
I've seen the DC-10 crossbleed start at idle. Good ol' CF6's.
Our fleet uses the GE and P&W types. Boeing's Vol I tells us to advance thrust to approximately 70% N2 for a cross-bleed start (which is done following SE taxi with the APU intentionally off).
Since we taxi around the ramp up to 80% N2, 70% N2 does not get my attention as being a hazard for airliners in our 6.
Bolty McBolt
28th Nov 2005, 02:59
Have seen the CF6 powered A330 do cross bleed start without nudging power up.
Shaka Zulu
28th Nov 2005, 13:01
@NONE is a x-bleed start requirement not to have a specific duct pressure according to Boeings Vol 1?
SZ,
No, there is none in our Vol I for a cross-bleed start.
"757/767-200/-300 Operations Manual
Supplementary Procedures - Engines, APU
SP.7.3
Engine Crossbleed Start
The APU must be shut down or the APU bleed air switch must be OFF.
Check that the area behind the airplane is clear.
Engine Bleed Air switch (operating engine) ......................................ON
Advance thrust on operating engine to approximately 70% N2 and
accomplish normal Engine Start procedure."
Perhaps you are thinking of the huffer cart start?
"Engine Ground Pneumatic Start
Check duct pressure 30 psi or greater.
Start engine using normal Engine Start procedure.
Two ground pneumatic air sources are required."
This time of year 70% N2 does in fact yield about 30psi.
Shaka Zulu
28th Nov 2005, 18:34
enlightenment! such a wonderful thing
Huffer cart was indeed the one ;)!
And yes 70%N2 in most cases ( a tat colder than ISA) gives roughly 30 psi in the ducting
SZ