Originally Posted by
Gold Digger
And now the starter motor to one of the engines has blown resulting in lots of vehicles with flashing lights surrounding the left side 😳😳. Apparently can cause a spark hence the appearance of the cavalry.
I'm sure the Captain was dumbing it down for the passengers.....
Bleed air Jet engines, don't actually have 'starter motors' as such. To start them they need need air pressure (bleed air) to spin the engine, provided by the APU (if the APU is dead, it's not uncommon and doesn't ground an aircraft, then they need a ground unit, basically a trailer with an engine to supply high pressure air to the aircraft to do the same thing), once the engine is spinning, fuel is introduced and the igniters (spark plugs for a jet engine) start the combustion process/engine kicks into life.
787's uses electricity to spin up the engine (from the APU normally, but it could be ground power as APU's do pack up) to do the same as it doesn't have bleed air, so it uses the engine generators on the engines to spin up the engine to start them up.