engines spooling down
 

i have noticed on more than one occasion when our based orange a319s taxi in on too stand that the engine on the captains side has already spooled down,does this cause "stress" too the airframe and is it done too save time on a already tight turnaround?purely curious.thanks in advance

I think its due to that side the Passengers come off, the jetty goes on that side and or stairs. So they shut Engine one off first.

In what sense would it cause stress to an already strong airframe, its normal I think for them to shut the engines down so quick. I noticed a BA A320 at EGLL T5 the other week, both engines and Beacon were off as soon as he applied the parking brake. I'm not an expert. Someone else will be able to clarify.

But I am pretty sure its so nobody putting the jetty or stairs near the door aft of the cockpit, is so they don't get sucked in. There more likely to go left side first than right so they passengers can disembark.

Regards,

R..

I'm not Orange but it is almost certainly a fuel economy measure. The engines on an A319 or 737 generate significant thrust even at ground idle, so one gives more than sufficient thrust for taxiing (unless you're trying to get it moving uphill from a standing start). There is some force turning the aircraft left but it is easily overcome with the steering tiller. The fuel saving is small on each flight, but it all adds up over an entire fleet. Perhaps suprisingly it doesn't save any time because the No.2 still has to wind down before the anti-collisions can be turned off.

It's purely fuel economy. Saves several hundred thousand a year. The Captain decides on which engine to shut down, depending on the expected direction of any low speed turns.

engine shut down on taxi.
if my memory is correct, i think virgin were doing the same.that was a lot of saving on fuel, which over 12 months is a lot of money. not sure if this practice still goes on with virgin. i wonder if savings being made this way is passed onto the pax in some way.??

Rough figures; an IAE V2500 engine on the A320 burns about 7kg of fuel per minute at idle thrust so single engine taxi-in is worth it. We (UK airline) are also allowed to do a single engine taxi out as long as several conditions are met. I recently did a single engine taxi out on a 321 and it got rolling with one engine at idle thrust at about 74 tonnes. If the gross weight is above 75.5t we have to start both.