Large generator type lorry

[Sonorguy]

We were coming back from Rome Ciampino last night via Ryanair 737-800. The plane was late boarding, which we initially put down to lack of staff (one slightly, well very, harrassed looking woman) on the gate. Once we'd all boarded the plane sat at the gate for a further 20-25mins without moving.

Then a large-ish rigid lorry appeared with something that looked like a big generator on the back and reversed up close to the engine. Driver connected it up somewhere we couldn't see and revved it hard while the pilot appeared to try an engine start. After a while and a few attempts the engine did appear to start and we left about an hour late. The flight was completely normal.

What did we see? We did wonder if it was a jet sized jump start pack, but it could have been something far less exciting! The other thing that crossed our minds was a very late appearance by the toilet waste removal truck totally unconnected with anything to do with engines but couldn't see enough detail to tell what the vehicle was.

[750XL]

An ASU (Air Start Unit). Provides air to start the engine when the APU is inop.

https://www.google.com/search?q=air+...air+start+unit

[PAXboy]

The 737 (like most airliners) carries an Auxilliary Power Unit, usually mounted at the back, under the vertical tail. if you search for 'Auxilliary Power Unit', then go to IMAGES.

The unit is a small jet engine and provides electric power when on the ground and then compressed air to rotate the engines as part of their start sequence. If the APU is inoperable, you can still take off as the unit is only for use on the ground, you just need someone to 'give you a swing', as we said in the old says.

[Sonorguy]

Thanks for the replies, that certainly fits as the plane was sweltering when we got on, as if the A/C wasn't working, and I understand that's also driven by the APU.

[WHBM]

Originally Posted by PAXboy

you just need someone to 'give you a swing', as we said in the old days.

Images of the engineer Hand Swinging a CFM56 .

[Johnny F@rt Pants]

Very disappointing, but not really surprising given the airline in question, that the welcome aboard PA didn't mention the non normal situation so that you would have known exactly what was going on. I do.

[PAXboy]

Fo that, you'd need an old school female Russian Ramp Lady. (allegedly)

[WHBM]

Originally Posted by PAXboy

Fo that, you'd need an old school female Russian Ramp Lady. (allegedly)

Not a joke. Travelling Y, boarded a Pulkovo (now Rossiya) 737 at St Petersburg one day seated in 2B. It was still rigged up for C class, with the window and aisle seats expanded and the narrow space in the middle. Knowing that such seats have a crank handle to wind them between configurations, I pointed to the seat and expected that, like BA, the tools would need to be produced to do this. But the purser shouted for colleague Sasha (female - in Russia this name can be either). Sasha, in the new elegant FA uniform recently introduced, strode forward, looked, pressed something, then grabbed both middle armrests firmly and WHAM ! Reconfigured.