View Full Version : Airbus and Transatlantic questions

13th Apr 2008, 14:17
I'm sorry to be curious - but there are a few mysteries I don't understand regarding the Airbus

What is the purpose of the Cross bleed valve? Why would you ever want to start the engines using the cross bleed? Is that all it is designed for? Is it designed so that in an engine failure, you can start the APU and feed both packs?

No idea.

Also, I heardthat to cross the Atlantic there is a stipulation that requires certain pieces of equipment - a sort of MEL if you will. Does anyone have a copy, or know the list of equipment required for atlantic crossing? because I heard a gut-shuddering rumour that they used to operate C152s STRAIGHT OVER the Atlantic, with extended fuel ranges.

I'm nervous enough when I'm C152 to Tatenhill!

13th Apr 2008, 16:36
In short thre intent of the cross bleed valve is to allow the interconnection of the two sides of the pneumatic manifold. This will now allow any of the operating air supplies to provide for the system(s) i.e pack, anti-ice (wing/engine) to continue to function that were supplied from the opposite side. This can as well be use to start the other engine(s) either on the ground or in the air.
With regard to your other question about the MEL. This is aircraft and operator specific as each aircraft has certain requirememts for this kind of opeartion. The other is dependant on the operator's approved operation,i.e. 180 or 240 Min. ETOPS.
Hope this is helpfull to you fornow.

13th Apr 2008, 16:37
I delivered a Cessna 210 across the pond to Holland - 8.9 hours non-stop from Gander to Shannon. All you have to do is disconnect the overwater sensor and the plane thinks it's over land the whole way. :hmm:

As for the Airbus, or any other transport category plane, I think you're talking about the required equipment for ETOPS. The MEL allows equipment to be inoperable, but many of those deferrable items are required for ETOPS operations.

13th Apr 2008, 16:43
My apologies in regard to your other question, as far as I am aware the Airbus does not have the air start function for its APU. Neither A-320 series or A330/340. Not quite sure for the -500/600 series. And why would you need the have air to start a shut down engine with additional air? The fact is even a windmilling engine may require supplimental air to get it up to a rotor speed to ensure a positive relight.

13th Apr 2008, 16:58
9 hrs from Gander to Ireland in a 210?! what speed were you doing?!!

Henry VIII
13th Apr 2008, 19:57
Canadapilot, you can cross the pond below FL 285 or above FL 420 without specific navigation equipment.
But if you want to cross it within the MNPS airspace (FL285/420 excluded) you have to comply with the Minumum Navigation Performance Specification. In first you find the minimun requirement in the MEL, on ground, other information and/or restrictions affecting further failure(s) are depicted in the MNPS manual and resumend in the AT(H/L) 1-2 Jeppesen chart.
Specifically to the Bus You can find navigation requirements for RVSM airpsace in FCOM 2.4.45 and remote areas flight in FCOM 2.4.46.
NAT details here:

General site (http://www.nat-pco.org/)

North Atlantic MNPS Airspace Operations Manual (http://www.nat-pco.org/nat/MNPSA/MNPSA_2005.pdf)

Enjoy, HVIII

13th Apr 2008, 22:17
thanks Henry, i'm kinda familiar with the NATS stuff, just always interested to read about ferry piloting and thought a 9hr crossing in a single engine was very quick!

13th Apr 2008, 23:18
AKAAB, you must have had a decent tail wind all of the way across the pond to achieve that route in that time!


14th Apr 2008, 22:21
It was a P210R at FL250 and I was throttled back a little to keep the cylinders on the new engine at a reasonable temp.

The crossing was a good challenge, but getting all of the logistics worked out for the crossing took a lot of time. The CAA inspectors in Moncton said I was the last guy that was going to be required to stop in for the waiver since GPS was becoming so widely used instead of old fashioned DR. That's my claim to fame, I guess.

The shop that installed the engine wanted me to go right out for the crossing while still on the original mineral oil without so much as an hour in the circuit. A quick call to the new owner convinced them that the engine needed at least ten hours and the first oil change before the crossing. (I think we actually put about 20 on it...)

14th Apr 2008, 22:53
The APU in both the A320 series as well as the A330/A340 family can be started throughout the flight envelope (same as in other modern airliners). It can assist an engine restart when below FL 250.

15th Apr 2008, 02:36
Reimers.very close ....
(2) Flight Operation.
The APU will:
- supply bleed air in flight up to an altitude of 6096 m (20000 ft.),

15th Apr 2008, 02:41
FL250 for APU battery start, FL 200 for APU Bleed assisted engine start.

Two "must" remember altitudes for all engine fail.

15th Apr 2008, 19:29
You need the cross-bleed option every time you have no APU and need to start an engine without ground air supply. Happens quite a lot. Those APU go broken from times to times and you can dispatch these aircraft without APU. All airliners have these feature.