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A320 Automatic Engine Starter Not Working

My son flew from Gatwick to Paris CDG this morning on an A320, gate departure was delayed 33 minutes. The reason given was that the automatic engine starter was not working and they had to wait for a starter truck to become available, it was starting another aircraft apparently.

Really?

It sounds like an unavailable APU (small support engine) so that there was no pressured air to start the main engines. For such occasions airports have "starter trucks" with a compressor available to deliver the required air.

Thanks for that.

Apparently, there was a bit of a que for them at Gatwick this morning.

I'm surprised that they can fly with an inoperative APU?

The APU is just that, an auxiliary power unit. It provides electrics and air while the engines are not running. Once the engines are up and running, the APU is generally shut down, and started again after landing. If it is totally U/S, then external electrics are also required.

Not a MEL item then?

I seem to remember that Chelsey Sullembergerrestarted his on the way down to the Hudson.

Quote:

Originally Posted by WB627 (Post 10474837)

I'm surprised that they can fly with an inoperative APU?
...........
Not a MEL item then?

Before go into the meat of this - for those reading this and being :confused: - The Minimum Equipment List (MEL), also commonly known these days as a Despatch Deviation Guide (DDG) is a document that lets a crew know what defects are “No Despatch” and OTOH those which are acceptable to take into flight and also any changes to rules or procedures caused by those defects.

APU inoperative may well be a MEL or DDG “item” but the book, whatever you call it, may well say despatch is allowed without the APU or components of it working as long as certain rules and procedures are followed.

Not having the APU available complicates things on the start ( you need the ground air truck to give you compressed air to spin at least one engine up for start, and you need ground electrical supply plugged in until you have an engine driven generator available) but after that, on many types, as long as there are no other problems with other elements of the engine driven electrical and air systems it’s usually “operations normal” until you get to destination.

FWIW on many of the “big twins” you can still do the likes of ETOPS without a serviceable APU, so I can’t see lack of an APU stopping a minibus from doing shorthaul sectors...but I suspect it adds more hassle to the crew’s working day.

Hi,

I'm rated on the A320. As others have alluded to, it sounds like a U/S APU which whilst not uncommon are a fairly normal part of day to day airline operations especially during the summer season where down time for maintenance is squeezed. Each airline has a specific authorised MEL for that aircraft type based on the MMEL (Master minimum equipment list) produced by the manufacturer which lists how long it can remain unserviceable for and what conditions need to be met for dispatch.

Operating without the APU isn't dangerous. It's just a pain and ups the flight crew's workload somewhat. What normally happens is an air start machine or truck is plugged in, an engine is started (normally the number 2 engine) on stand and then the pushback is completed. The tug disconnects and the crew will then perform what is known as a crossbleed start. In essence this uses engine bleed air from the operating engine to start up the other engine. Once both engines are running, it's pretty much ops normal with the main difference being that you only have 2 'generators' (excluding the RAT) so if you lose an engine (highly unlikely), some non essential systems may be shed.

I hope that helps.

Champ

Generally, providing all is well, the APU is not required while airborne. An example of its use would be a failure of an engine-driven generator. The B737 (and I presume the A320) has three, one on each engine, and one on the APU. Loss of one of the engine-driven ones would necessitate the APU being started. Single generator is generally an emergency procedure, albeit not major. In fact, I've actually flown sectors where an EDG was U/S on departure. The MEL (DDG) said this was acceptable, provided the APU and its generator were on line for the whole flight.

Thank you all for your answers. Most enlightening.