A320 engine wouldn't start --> external truck used?

[stijndp]

Hi guys,

Yesterday (early in the morning) I flew from Barcelona T1 to Brussels airport with an Airbus A320 of Vueling Airlines. I guess it was the first flight for the day of the plane.

The pilots tried to start the left engine 2 times but they were unable to start it. The right engine wasn't running either. About 5-10 minutes later some kind of small truck arrived and the ground crew rapidly attached some kind of hose to the plane. They fired up the truck and the pilots tried to start the engine again. This time the left engine did start, followed by the right engine. There weren't any problems during the rest of the flight.

Is it normal for something like this to happen
What exactly could the small truck have been Maybe an air compressor

[jdw]

The small truck you saw is a pneumatic compressor. probably the APU bleed air didn't work to start the main engines. With the compressor they can start the main engines via the pneumatic duct.

grtz

[flightlover]

The little truck you saw is called "jetstarter". It's quite commenly used to jumpstart (mostly larger) planes when they are unable to start on their own.

[cnc]

jetstarter? here we call it an airstarter

[regi]

and what if that engine stops in flight and has to be restarted?

[Homo Aeroportus]

For those speaking "alphabet" :
A.S.U. Air Start Unit


An ASU can also be used to air condition the aircraft via the air cycle machines, packs, on board. Strange but yes, blowing warm air to cool down the cabin.

Cheers

H.A.

[Homo Aeroportus]

and what if that engine stops in flight and has to be restarted?

Then swicth On the APU, Auxiliary Power Unit. Kind of a small jet engine, usually installed in the tail, producing electricity and compressed air.
This is used "normally" on the ground to air start the first main engine, though not a smart way to transform fuel into noise and air.
The 787, seven late seven, will have an electric start of its main engines; hence a third ground power connector behing the LH wing.

Using APU in flight is a sign of a bad day, though it can save it.
Just ask Capt Moody, commander of the Flying Ashtray, B747 that flew through volcano ashes at night that killed all four engines. APU and some windmilling enbaled starting the engines again.

Cheers.

H.A.

[regi]

and what if that engine stops in flight and has to be restarted?

Then swicth On the APU, Auxiliary Power Unit. Kind of a small jet engine, usually installed in the tail, producing electricity and compressed air.
This is used "normally" on the ground to air start the first main engine, though not a smart way to transform fuel into noise and air.
The 787, seven late seven, will have an electric start of its main engines; hence a third ground power connector behing the LH wing.

Using APU in flight is a sign of a bad day, though it can save it.
Just ask Capt Moody, commander of the Flying Ashtray, B747 that flew through volcano ashes at night that killed all four engines. APU and some windmilling enbaled starting the engines again.

Cheers.

H.A.

But that is in fact what I meant. If the engine could not be started on the ground by the APU, and they allow the airplane to depart after a start with a external unit, there is no safety in case the same engine would stop during flight.
I remember a 2 hour delay at AMS with a brand new B747-400 of KLM ( in 1991 I guess) because something was wrong with the startinguipment. They had to replace a part.

[jdw]

and what if that engine stops in flight and has to be restarted?

Following the MEL (minimum equipment list) the APU is not required if the aircraft doesn't fly ER operations.
So if you lose an engine you can still use bleed air from your other engine witch is still running. In the worst case if you lose both engines the only option (without apu) is land asap.

[SN_fan]

But that is in fact what I meant. If the engine could not be started on the ground by the APU, and they allow the airplane to depart after a start with a external unit, there is no safety in case the same engine would stop during flight.

If that engine would need a restart couldn't they just use the other engine to supply for the compressed air or whatever they would need to start an engine ? And also isn't airflow from that flying aircraft sometimes not sufficient to start it again ?

[HAWK21M]

Sounds like a Pneumatic Jet Starter was used to supply Bleed Air for Engine start.Normal & safe procedure.

On the topic of Engine Restarting....Firstly its rare that an Engine will shut down unless its fuel supply is cut off or Ignition is affected in heavy rain or turbulence,or contamination to the Airflow like volcanic dust.

The Engine can be restarted in Air due to its Windmilling effect or Bleed air can be used for a cross start from the running engine.

[regi]

OK, I understand it. So my worries were unnecessary.

[NimbusFlyer]

If one engine fails, you still have electrical power from the other one. If no more electrical from the second engine, there is also the RAT (Ram Air Turbine) that can provide either electrical or pneumatic power if needed and in the worst case you can fly for about 20min on batteries. So enough redundancy to find an airport and land.

[jdw]

If one engine fails, you still have electrical power from the other one. If no more electrical from the second engine, there is also the RAT (Ram Air Turbine) that can provide either electrical or pneumatic power if needed and in the worst case you can fly for about 20min on batteries. So enough redundancy to find an airport and land.

The RAT doesn't provide pneumatic power but only electrical and hydraulic power to a limited number of intruments and systems.

[cnc]

For those speaking "alphabet" :
A.S.U. Air Start Unit


An ASU can also be used to air condition the aircraft via the air cycle machines, packs, on board. Strange but yes, blowing warm air to cool down the cabin.

Cheers

H.A.

yes pressure is reduced to 30 PSI and commander must open packvalves when used as airco unit

[Bracebrace]

Using APU in flight is a sign of a bad day, though it can save it.
Just ask Capt Moody, commander of the Flying Ashtray, B747 that flew through volcano ashes at night that killed all four engines. APU and some windmilling enbaled starting the engines again.

Is that stated in the report? I never read it, so I honestly don't know, but I always thought it was windmilling only.

On the 747-400, APU cannot be started in flight. The idea being: if one engine fails, you have 3 APUs available (the other engines). If two fail, there are still two giant APU's available. If three or four engines failed... the source of the problem would then probably be common for all engines: either an air problem (like here, volcanic ash), or a fuel problem (contamination). In both cases, your APU would be confronted with the same problems, so it would fail as well when you try to start it.

I guess passengers quickly make the logic step from starting an engine on the ground with the APU, to expecting to do the same thing in the air. This depends on altitude and speed.

The APU is much more an electrical and pressurization backup at lower altitudes. For two engined aircraft (737 ie), the APU is used for inflight restarts, but then only in certain flight situations (based on altitude and speed). Starting an APU at higher cruising levels puts an enormous thermal strain on the machine and it tends to fail quite a lot. Therefore In case of dual engine failure it can even get more tricky since starting the APU drains the battery as well. It's a "try only once" item. And keeping in mind its possible starting difficulties at higher altitudes, you better try pure windmilling as long as you have the altitude.

Cheerz

[regi]

STOP
I am getting scared again.

[Homo Aeroportus]

I don't seem to remember having read the official report. Rather the book written by one of the pax after interviewing others and the crew.

Capt Moody elected to switch the APU On though the procedure does not allow this above 28 000 ft (?), but he would have decided that the APU doesn't read the book anyhow

They also kept a shallow diving attitude to maintain windmilling.
One engine relit after a while and this enabled starting the others, though N°2 had to be later swicthed off due to erratic behaviour.
So they ended up with a 3-engine crippled plane, scary changes in thrust, unreliable instrumentation (blocked pitots) making an approach at Jakarta that had the ILS GS u/s, and looking through a sandblasted windshield.

I think the APU is on the MEL for ETOPS so thy may have to switch On during flight.
Actually the A380, that has a biiiig APU with two generators 120kVA each, may also switch it On before T/O :

.... during the take-off the APU supplies bleed air to the ECS (thus avoiding
a reduction in engine thrust) and in flight it backs up both electrical and air conditioning systems

Cheers.

H.A.

[earthman]

This is the APU used by Ryanair:

[flightlover]

This is the APU used by Ryanair:

I think this one is a bit to big, but pedals underneath the seat are not.

Strange they didn't think of a take-off flinstone style