Taxi on one engine
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Taxi on one engine
Well we all see it today, for fuel conserve purposes, most of the airlines perform one engine taxi procedures.
Now, my question is (for airline and small aircraft operators), how much is this operation "different" than the normal 2 engine operation? Is it harder, are the movements and turns different? Does it require a bit forward thinking?
Thanks in advance.
Now, my question is (for airline and small aircraft operators), how much is this operation "different" than the normal 2 engine operation? Is it harder, are the movements and turns different? Does it require a bit forward thinking?
Thanks in advance.
No difference at all really in a jumbo...we shut down no 3 after 3 min at idle. I think chopping 2 and 3 is coming in soon in our company .(fuel economy)
As I recall in a twin (73 size) it's no big deal, but you try to keep the momentum going until you're on stand.
As I recall in a twin (73 size) it's no big deal, but you try to keep the momentum going until you're on stand.
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I think quite alot of the time its to do with the moment from front wheel steering.
On quite short length aircraft you have to be quite carefull shutting one down. The radius of turn turning into the working engine is significantly larger than into the dead one. You would end up with quite a sore wrist as well as the tiller forces go up as well.
To be honest its really not worth the hassel for the <10kg of fuel you are going to save. For the big aircraft eg 747 they use as much fuel taxing as we do in a 2 hour sector. So Big savings
On quite short length aircraft you have to be quite carefull shutting one down. The radius of turn turning into the working engine is significantly larger than into the dead one. You would end up with quite a sore wrist as well as the tiller forces go up as well.
To be honest its really not worth the hassel for the <10kg of fuel you are going to save. For the big aircraft eg 747 they use as much fuel taxing as we do in a 2 hour sector. So Big savings
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I used to do it in piston twins and now do in small jets and it's no problem at all, just make sure in smaller aircraft if you are turning into the live engine that you have the speed to carry you round the corner. If you power up it all starts working against you.
Its SOP in EZY. 140 a/c doing 8 sectors 364 days a year saving 10kgs of fuel equates to an annual fuel saving of four thousand and seventy seven tons at a typical cost of £500 a ton which is two million and forty thousand pounds on the bottom line. The numbers are scary!
Single engine taxi can often save much more than 10kgs. You can save 10kgs by not running the APU bleed air for 20 minutes of turnaround. You can save another 10kgs by starting the engines 60 seconds later on pushback.
With oil heading to $110 a barrel fuel micromanagement is becoming an ever bigger factor in the day to day trade of an airline pilot.
WWW
Single engine taxi can often save much more than 10kgs. You can save 10kgs by not running the APU bleed air for 20 minutes of turnaround. You can save another 10kgs by starting the engines 60 seconds later on pushback.
With oil heading to $110 a barrel fuel micromanagement is becoming an ever bigger factor in the day to day trade of an airline pilot.
WWW
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There is no problem steering the A319 on single engine, but you have to use common sense when to do it and when not to. If you have done it in an airport like Madrid you risk having to put way too much thrust on the remaining engine when you go on stand as it can be very uphill sloped 
You have to remember that you can not just slam on 60% N1 when you are so close to the gate and it has happened before that the crew had to turn on the second engine again because they had to come to a complete stop on the slope due to obstruction reasons. Doh!
It is actually more annoying to taxi with engine anti ice on as the the N1s are considerably higher than normal idle. In low vis it is not desireable to approach 30 kts constantly as it is difficult to see anything in 125 m RVR
If it is a long taxi then you have to keep an eye on the brake temperatures as you use the brakes quite often.
You have to remember that you can not just slam on 60% N1 when you are so close to the gate and it has happened before that the crew had to turn on the second engine again because they had to come to a complete stop on the slope due to obstruction reasons. Doh!It is actually more annoying to taxi with engine anti ice on as the the N1s are considerably higher than normal idle. In low vis it is not desireable to approach 30 kts constantly as it is difficult to see anything in 125 m RVR
If it is a long taxi then you have to keep an eye on the brake temperatures as you use the brakes quite often.
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malc4d
SOP in our airline too. There is no problem taxying on one engine on our types (73/75/76) but you have to use common sense and follow the guidelines. As has been pointed out, turning is not a problem (unlike in your Seneca!), the issue is slope and stopping/starting using more than desirable thrust. Some of the guidelines are;
1. No SETI in adverse conditions (such as contamination/ LVOs)
2. No SETI with aircraft un-serviceabilities which may affect required systems.
3. All engines must get the standard Boeing cooling period before shutdown, which on the 737 is three minutes at idle/ taxy power settings, so sometimes the taxy in will be too short.
Airmanship decisions on whether to SETI or not include considerations of slope, aircraft weight, complexity of taxy route, familiarity with airfield/ taxy route, weather conditions (especially with regards to surface condition and slope), crew considerations such as workload, tiredness level, experience level (of one or other crew members in their respective seats/ if suitable experience level has been met if a training flight), considerations if having to cross an active runway during SETI, consideration of which engine to shut down based on the anticipated turns, especially final turn onto stand, and I am sure there are more that I can't think of right now!
So, it is not hard, but takes some thinking about, planning for and briefing BEFORE you land and further consideration after taxying clear of the landing runway before you confirm that you are happy to do it. As WWW has pointed out, there are significant savings to be made if EVERY pilot can consider it and when suitable do it across a fleet over a year. For us it is to be considered as SOP to SETI, but the decision rests with the captain and there is no pressure to do it if the captain decides it is not suitable.
PP
SOP in our airline too. There is no problem taxying on one engine on our types (73/75/76) but you have to use common sense and follow the guidelines. As has been pointed out, turning is not a problem (unlike in your Seneca!), the issue is slope and stopping/starting using more than desirable thrust. Some of the guidelines are;
1. No SETI in adverse conditions (such as contamination/ LVOs)
2. No SETI with aircraft un-serviceabilities which may affect required systems.
3. All engines must get the standard Boeing cooling period before shutdown, which on the 737 is three minutes at idle/ taxy power settings, so sometimes the taxy in will be too short.
Airmanship decisions on whether to SETI or not include considerations of slope, aircraft weight, complexity of taxy route, familiarity with airfield/ taxy route, weather conditions (especially with regards to surface condition and slope), crew considerations such as workload, tiredness level, experience level (of one or other crew members in their respective seats/ if suitable experience level has been met if a training flight), considerations if having to cross an active runway during SETI, consideration of which engine to shut down based on the anticipated turns, especially final turn onto stand, and I am sure there are more that I can't think of right now!
So, it is not hard, but takes some thinking about, planning for and briefing BEFORE you land and further consideration after taxying clear of the landing runway before you confirm that you are happy to do it. As WWW has pointed out, there are significant savings to be made if EVERY pilot can consider it and when suitable do it across a fleet over a year. For us it is to be considered as SOP to SETI, but the decision rests with the captain and there is no pressure to do it if the captain decides it is not suitable.
PP
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To be honest the addition wear and tear on the tyres and brakes would proberly cost more than the fuel saved for us.
Another example is reverse thrust above idle. What are the associated costs regarding engine and brake wear/ maintenance? It would appear that idle reverse rather than detent costs less overall as brakes tend to be cheaper than engine service costs. But, factors like carbon brakes as opposed to steel change that equation and you need to get carbon brakes hotter for reduced wear, so lots of factors to consider to get the TRUE value or not of a procedure.
PP
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I shut down the left engine on a Cessna 310 cargo due to low oil while taxiing and all you do is go round and round in tight lefthand circles !!!!!!.
No matter the powersetting. Needed a tow back.
Steve
No matter the powersetting. Needed a tow back.
Steve
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Yep agreed on the small props being problematic. I tried this once on an Aztec when rolling and it was just about OK. As soon as I came to a stop it was impossible to start off and keep it straight, your would just end up going in circles....
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Another thing to think about as well...
Is your bum covered.
If you don't have any SOP's to cover doing it and anything goes wrong they can hang you out to dry.
PP's and WWW's companys it seems have produced SOP's which will have been approved by the CAA flight ops inspectors. My company doesn't hence I don't do it.
Is your bum covered.
If you don't have any SOP's to cover doing it and anything goes wrong they can hang you out to dry.
PP's and WWW's companys it seems have produced SOP's which will have been approved by the CAA flight ops inspectors. My company doesn't hence I don't do it.
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Certainly makes no difference with a bigger TP. When in New York LGA, we will often taxi out on one engine and start it about 5 mins before cleared for take off. Most of the jets do that as well, but then is it usually an hour taxi in LGA! (Good for the pay check)
When we come in, we just wait for the ITT to stablize and then shut down number one as that is the side pax get on/off. If we are doing a quick turn however, leaving two spinning is not unusual. It saves on the batteries and the engines (at $3m) by not starting too often.
When you pull the condition lever to fuel off, you do feal a suddent pull to the left on the tiller, but it's no problem. Biggest thing is not to do it at night as without two engines running, the reading lights don't work, so its a pax comfort issue
I used to do it at AFT in Exeter too, when going from the fuel pumps to parking in a BE76. No problems there.
When we come in, we just wait for the ITT to stablize and then shut down number one as that is the side pax get on/off. If we are doing a quick turn however, leaving two spinning is not unusual. It saves on the batteries and the engines (at $3m) by not starting too often.
When you pull the condition lever to fuel off, you do feal a suddent pull to the left on the tiller, but it's no problem. Biggest thing is not to do it at night as without two engines running, the reading lights don't work, so its a pax comfort issue
I used to do it at AFT in Exeter too, when going from the fuel pumps to parking in a BE76. No problems there.
