Single engine taxi
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Single engine taxi
Many airlines, including my own, have a "Single Engine Taxi In" procedure. Does any one have one for taxiing out? Particularly for wing mounted twins. I understand that tail mounted types may have been doing this for some time. Also that tri-jets have taxiied out with No.2 shut down.
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It was used at my old outfit in the US (737), then prohibited (we merged with someone who didn't do it), then put back into use, then stopped again, then slowly came back into use. I left in 2006 so I'm not sure what's going on now. Looking at the previous sentence, I'm not sure if management knew what was going on, either. 
Over here (India) it's uncommon. Ramp clearances are usually tight and crowded; you'd be certain to blast somebody while moving out. Once away from the ramp in a long lineup, some of us elect to shut an engine down, but it's not an approved procedure.
Over here (India) it's uncommon. Ramp clearances are usually tight and crowded; you'd be certain to blast somebody while moving out. Once away from the ramp in a long lineup, some of us elect to shut an engine down, but it's not an approved procedure.
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One (or two) engine-out taxi
Outside of considerations such as company approved procedures, you better be extremely careful with taxiing with engine(s) out. And definitely for twin-engine airplanes such as B737 or A320.
xxx
Yes, the 747 can taxi with one engine (or even two engines) shut down, which depends on weight. With the 747, I taxied-out frequently on 3 engines, and at times taxied-in on 2 engines. Again, depends on circumstances and weight. The 747 normally will use outboard engines for taxi, while the 707 or DC8 used the inboards (because of hydraulic pumps). In the 727, we often taxied with engine nš 3 shut down, again hydraulic system considerations.
xxx
With a twin, there are other considerations, and your airplanes are all different. You have to think about hydraulic back-up (for brakes) and also AC electrical supply (1 generator - or do you keep the APU operating as a back-up). Finally, moving a 737 or 320 (even light) will require quite a bit of thrust from only one engine, which is not too nice for the airplane behind you.
xxx
Then we come to the stupid company procedures where a chief pilot decides "thou shalt, (or shalt not) taxi with X engine", able or unable to justify his decision to make it SOP or not. Happened to a friend of mine piloting a Lear 24D a few years ago. His company procedure was to start the RH engine (opposite of the door) as soon as the last passenger stepped into the airplane (to appear to be "efficient"), then the co-pilot closed the door, and they taxied-out on RH engine. Same thing for arrival. Shut down the LH engine and use the RH engine again for taxi-in, the co-pilot jumping out of his seat for the last few meters on the ramp, and quickly opened the door, while the RH engine was unwinding.
xxx
Imposing a SOP with no system knowledge was wrong. One day, the RH engine generator failed in flight. So, on arrival, instead of taxiing-in with the RH engine, they traded and taxied-in with the LH engine, which had the only operating generator.... Unknown to them. the hydraulic pump of the LH engine was inoperative. Co-pilot went to open the door... the pilot tried to stop the plane on the apron, but, with NO hydraulic pressure, he could not stop the airplane. He had to quickly reach for the switch of the electric hydraulic pump, avoiding to hit a fuel truck with the nose of the Lear...
xxx
In a Lear, you taxi-out on one engine (which permits you to check 1500 PSI out of that hydraulic pump) then after the flight, you taxi-in on the OTHER engine (to see if the other hydraulic pump operates). It is a procedure that is NOT in the book, but all Lear pilots should observe. I hope they have separate warning lights on these new Lears for the hydraulic pumps.
xxx
Happy contrails
xxx
Yes, the 747 can taxi with one engine (or even two engines) shut down, which depends on weight. With the 747, I taxied-out frequently on 3 engines, and at times taxied-in on 2 engines. Again, depends on circumstances and weight. The 747 normally will use outboard engines for taxi, while the 707 or DC8 used the inboards (because of hydraulic pumps). In the 727, we often taxied with engine nš 3 shut down, again hydraulic system considerations.
xxx
With a twin, there are other considerations, and your airplanes are all different. You have to think about hydraulic back-up (for brakes) and also AC electrical supply (1 generator - or do you keep the APU operating as a back-up). Finally, moving a 737 or 320 (even light) will require quite a bit of thrust from only one engine, which is not too nice for the airplane behind you.
xxx
Then we come to the stupid company procedures where a chief pilot decides "thou shalt, (or shalt not) taxi with X engine", able or unable to justify his decision to make it SOP or not. Happened to a friend of mine piloting a Lear 24D a few years ago. His company procedure was to start the RH engine (opposite of the door) as soon as the last passenger stepped into the airplane (to appear to be "efficient"), then the co-pilot closed the door, and they taxied-out on RH engine. Same thing for arrival. Shut down the LH engine and use the RH engine again for taxi-in, the co-pilot jumping out of his seat for the last few meters on the ramp, and quickly opened the door, while the RH engine was unwinding.
xxx
Imposing a SOP with no system knowledge was wrong. One day, the RH engine generator failed in flight. So, on arrival, instead of taxiing-in with the RH engine, they traded and taxied-in with the LH engine, which had the only operating generator.... Unknown to them. the hydraulic pump of the LH engine was inoperative. Co-pilot went to open the door... the pilot tried to stop the plane on the apron, but, with NO hydraulic pressure, he could not stop the airplane. He had to quickly reach for the switch of the electric hydraulic pump, avoiding to hit a fuel truck with the nose of the Lear...
xxx
In a Lear, you taxi-out on one engine (which permits you to check 1500 PSI out of that hydraulic pump) then after the flight, you taxi-in on the OTHER engine (to see if the other hydraulic pump operates). It is a procedure that is NOT in the book, but all Lear pilots should observe. I hope they have separate warning lights on these new Lears for the hydraulic pumps.
xxx
Happy contrails
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Gatwick incident
Do I not remember CityFlyer having an accident at Gatwick a few years when taxiing in on one engine, having a hydraulic problem resulting in no brakes and hitting a GPU with the prop?
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BOEING allows B737 single engine taxi but the APU must be ON.
The rest is common sense,no uphill,standard speeds,taxi apron not contaminated,and some basic airmanship...
Captain Standard.
The rest is common sense,no uphill,standard speeds,taxi apron not contaminated,and some basic airmanship...
Captain Standard.
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Thanks for the replys fellas. Please keep them comming.I must admit, speaking as a pilot who once started the take off run with out any flaps I do wonder if what is the likelyhood of opening the taps only to find one engine is not running. The flaps incedent was two hours into discresion at 0900 local in a Balieric. Of course the config warning made it a non event, we got no faster than walking pace. I had 3000 hrs at the time , I have 10000 more now.
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From an engineering point of view taxying a wing mounted twin on one engine would put a lot of side load into the nose leg especially when trying to move from a standstill.
