A320 Early Engine Shutdown?

[TimV]

I regularly pax on A320s and their derivatives. I've noticed a few times now that after landing if there is a delay in parking at a stand it sounds as if the engines are shut down - the APU coming on at the same time (as indicated by the usual flicker in the cabin lights) - and then the a/c finishes its taxi in that state. Is the APU being used to taxi the aircraft? Or is there some element of the main engines that is shut down but they are still capable of moving the a/c at low speed?

[Off Stand]

At some airlines, they have a proceedure that involves shutting down one engine for taxying.

[BRISTOLRE]

A lot more of this is done these days as fuel saving measures. Shutting down of one engine/single engine taxi is a very valid exercise. I noticed it on a Midland A319 exiting LHR 27R last week.

[FlyUK]

The 319/320/321 burn about 400kg/hr at idle per engine. You can quite easily taxi on one engine at idle thrust most of the time, so, certainly where I work, we shut one down after landing.

[saman]

TimV, to answer your direct question, no, you cannot taxi on the APU, it provides air conditioning air, Electicity and Hydraulic power but no meaningful thrust. And no wheels are powered on any aircraft I can think of.

[TimV]

Thanks folks - it was on bmi flights that I noticed this so it must be a company policy. :ok:

[barit1]

It was SOP for some operators at least 30 years ago - the only caveat was that a cooldown period (maybe 2 minutes) should be observed unless negligible R/T was used.

In fact, 40 years ago I rode a DL DC-6 into ORD and noticed R-2800 #4 was idling slower than the others during the long taxi. It finally died well before we reached the gate------ but I doubt this was intentional. :cool:

[GOLF-INDIA BRAVO]

Have often noticed it with prop aircraft ( probably because it is easy to see )
and wondered if it had a safety implication when on stand with the ground crew milling around

G-I-B

[jedigtr]

It's normal practice to shut an engine down when taxiing to stand, I often see it at work bmi and BA shorthaul do it all the time and you even see some of the longhauls taxiing with the outer 2 engines shutdown:)

[HEATHROW DIRECTOR]

Guess people aren't aware of it so much with jets. In the old days of props you'd often see Viscounts shut down the outer two as they left the runway..

[JetSetJ]

Hi there,

I was at HeathroW yesterday for a number of hours waiting for my flight. I noticed all the BMI A319/320 seemed to close their engines down adjacent to the taxi way that is currently being worked on ( approx 1/3 of the way down 27R)! I presume this must be part of their SOP's?? As non of the other airlines, BA, IB, AZ, LH didn't seem to do this?

Regards

JetSetJ

[barit1]

Are you sure you aren't seeing reverse thrust deployed? The only way you'll see an engine shutdown is if you're looking straight into the inlet - or at the gages.

[JetSetJ]

Hi there,

I am absolutely sure it wasn't reverse thrust as i could see into the engine inlets and heard the engine shutdown:8

It seemed to be the starboard engine. I was watching this in Heathrow's terminal 1 where there is a seating area where you can watch the aircraft taxi past at extremely close proximity, the only downside of this area is that it is located adjacent to the smoker's area:(

Regards

JetSetJ:ok:

[NudgingSteel]

I was the Ground Movement controller at a regional airport some years back, when an Airbus 320 taxying to stand, turned inbound to the stand centreline then stopped about 30 metres short of where he should have. The pilot explained that they were taxying on one engine and the main wheels had settled in a very slight dip (a grated drainage channel) that ran across the back of the stands. Normally such a slight dip was barely noticeable, but they considered that they'd have had to use so much power from the one engine to move forwards again, that it would have created a jet blast hazard on the apron. Remaining engine shut down and aircraft eventually towed onto stand by a tug.

[TURIN]

A certain Irish airline used to shut ALL engines down as they turned onto the stand. Mind you, they did taxi in at about 40mph too.:=