SurClaro Flight Simulator Resources

lc · Posted: Fri Apr 27, 2007 8:29 pm Post subject: Drama today!

:o Jeez, couldnt wait to tell y'all this, i had my 1st emergency today! But I was cool about it all 8) !, we had a small APU drama when It suddenly shut down during my flight from EGKK or LGW as you may know it (London Gatwick) to mallaga, España! obviously its role is to keep the passengers cool so they started to get unbearably hot but just as we were about to make an emergency landing, it started up again. easyJet are going to tell me and Captain J. Munroe (snooze cruise) the cause of it! im cool! 8) 8)

crazydunc · Joined: 18 May 2006 Posts: 243 Location: Gloucester, UK

hehe! well done mate! was it a 737?

dunc

heeshung · Joined: 07 Dec 2005 Posts: 554

Hmm...interesting... I always thought the APU almost never operated in-flight, and that the A/C is driven by the engines in-flight...

Guess I do learn something new everyday.

Behrentzs · Joined: 16 Feb 2006 Posts: 579 Location: Denmark

I thought that too.

lc · Posted: Sun Apr 29, 2007 5:35 am Post subject:

:D 8) we only operate the APU sometimes and yes it was a 737 but not my 800 it was an older 400 model! 8)

heeshung · Joined: 07 Dec 2005 Posts: 554

If the APU shut off in flight and it was powering the A/C, couldn't you have switched A/C responsibility to the engines instead?

rd · Posted: Mon Apr 30, 2007 5:50 am Post subject:

I'm thinking this is bogus......Tread carefully lc.

RD

Ice · Joined: 27 May 2006 Posts: 179 Location: England

once engines have started and you have pushed from gate, normally the power and air supply is fed from the engines, the apu is then shut down as it is no longer needed.

However i think its slightly different on the bigger aircraft like the 747s

I think they leave the apu running to supply the aircon in order to squeeze that bit more power out of the engines to make sure they get off of the ground before runway end, then they switch to engines and shut that down.

The maximum altitude for an APU running bleed air is 17,000ft so if you where going from Gatwick to Mallaga your cruise would be around 35,000ft so the APU would have to be shut down.

Correct me if I'm wrong, but somehow this does not seem right, so further explanation is needed as i am not convinced.

bromster · Posted: Mon Apr 30, 2007 3:03 pm Post subject: spot the phoney...

Agreed.

An APU is still an APU, regardless of the aircraft. Even a 737-200 is the same. APU is shut down on taxi and turned on again after landing. All systems run off the engine-bled air during flight. Using the APU would be a waste of fuel.

Also, with no air-conditioning and an outside temperature of -30 degrees celcius, I certainly wouldn't be getting HOT!

Someone needs to strip this dude of his plastic wings before he kills someone...

Oh... by the way... a broken APU is not uncommon, especially among ageing aircraft. It's DEFINITELY not an EMERGENCY!!! :? .

If anyone's interested....... All you need is a GPU (Ground Power Unit) Truck waiting when the aircraft pulls into the parking bay. The GPU gets plugged into the aircraft (where the engineer plugs his headset in) before they shut the engines down. The truck then acts in place of the APU whilst the aircraft is parked. The GPU provides alternate electrical power for engine start, whilst a COPCO provides an alternate Air Supply for engine start.

Bromster.

sonicboom2885 · Posted: Mon Apr 30, 2007 7:30 pm Post subject:

RD - was thinking....
ADD? ADHD?
i dunno, seems plausable.

EDIT..BY...umm...errr,.....uhhhh, Ah, forget it. What are you trying to say there sonic......You don't want to hit 100 posts. :wink:

groundsquirrel · Posted: Tue May 01, 2007 2:03 am Post subject: I'd..

I'd rather troubleshoot a Lincoln Mark VIII with a random misfire.... :)

sonicboom2885 · Posted: Tue May 01, 2007 11:24 am Post subject:

LOL RD n GS LOL

Cloud Chaser · Joined: 04 Apr 2007 Posts: 10

Most of the airlines I've worked with have the procedures dictating the pilots to have the APU off before takeoff, with both engines running. In a normal situation, even if one engine failed, the other engine would be able to provide sufficient electrical, hydraulic, and pneumatic pressure to the flight deck, with the standard emergency load shedding to the cabin. Therefore, having the APU running in flight (although possible) isn't done on a normal day. Even if it was running in flight, for one reason or another, it simply switching off wouldn't affect anything on the flight deck or the cabin, unless the EDGs were not connected to the main Bus (which isn't allowed).

Mr. LC - I am having a slight feeling you aren't quite what you represent yourself as. In fact, you have not provided any valid proof you've ever flown anything more than a paper airplane. :evil: Please stop embarrassing the trait of flying commercially with your lack of knowledge and unfulfilled childish dreams.

EDIT: Ice, there are two takeoffs (and two entries in the performance manual) a pack on, and a pack off takeoff, and they differ in engine capabilities. But the packs are turned back on after takeoff, to continue their role of maintaining the cabin comfortable for the passengers. APU is not used to compensate - as mentioned 999 out of 1000 flights it is switched off once a reasonable takeoff slot is received.

Cloud Chaser - a real 737 pilot.

sonicboom2885 · Posted: Mon May 07, 2007 12:23 pm Post subject:

Ouch, what a spanking.
=)
CC - which airline u fly for?

Cloud Chaser · Joined: 04 Apr 2007 Posts: 10

I started off with Lufthansa on the 737 type, but I'm currently working with All Nippon on a temporary basis.

Oh, and PS - he asked for it ... :wink: