Single engine taxi out?

[MONSIEUR]

A few days ago, we were taxying out in LTN, and an EZY airbus coming towards us seemed to have only one engine running.. He defo was taxying out for departure too.
I was just curious to find out if this is a standard procedure at EZY or any UK airline, considering all the possible implications and restrictions of such procedure...

[CY333]

Seen this one before actually, a captain we had was doing this.

I dont believe is wise , in my opinion.

Imagine going to the holding point and you got a failure on the engine you just started and your MEL considers it as a NO GO item.

You are just making everyones life difficult.

Theres a reason to follow SOPs.........

[MONSIEUR]

Agreed.. but thats precisely why I've asked if it actually is an SOP at EZY. and If so what conditions must be met,what are the restrictions etc.. (other than capt's discretion obviously)

[Dan Dare]

The bean counters in orange land seem to think they can save pennies by only having one engine running on the ground. On paper of course this is a marvelous idea, but what they don't see is:-

• By not being ready at the holding point they loose opportunities to get airborne sometimes costing them 10 minutes or more holding.
• If they break while starting at the head of the queue then there is no end of trouble getting them out and keeping movements going.
• At a busy airport the wasted runway movement may not be made up until the end of the day - in effect every flight from the airport for the rest of the day is delayed by one orange aircraft not being ready.
• When pilots try to blag it and accept line-up clearance anyway with the expectation of being ready when cleared take-off (you wouldn't believe it, but some honestly think this is acceptable) the ensuing missed approach is fairly likely to also be oragne these days.
• When taxiing in and a tight turn in the wrong direction is required the taxyway is blocked (delaying another orange aircraft) while they re-start the other engine to enabble the turn.

Recognising some of this orange management have now requested that ATC inform pilots when they are e.g. number 3 to depart. Of courrse this still takes away any flexibility to make better use of a busy runway by flexibility.

So any shareholders reading this far perhaps you could encourage the bright sparks that came up with this idea to get aircraft ready by the time they get to the holding point.

[greenfreddie]

Taxied out single engine on 4 of my last 10 or so sectors (taxied in single engine on 9 of them - the only exception being a very short run into the gate) - it's like anything - the more familiar you get, the less of a drama it is. It takes a little bit of judgement, but then again what doesn't? Obviously there is a fine balance between saving a drop of fuel and being caught out, so as a rule of thumb if there are 3 aircraft at the holding point or less I'd be inclined to be good to go on arrival, I stick to familiar airfields and make sure the guy/girl next to me is 100% happy to go along with it, but within the bounds of reason, why not?

[MONSIEUR]

interesting to hear about it from someone who actually does it.. Greenfreddie do u work for EZY then?

[greenfreddie]

Guilty as charged....

[Gary Lager]

orange A319/320 ops:

Yellow HYD pump ON before Eng 1 start,
Eng 1 start.
After start 'scan' (setting flaps/trim APU Bleed OFF), but no after start checklist yet;
clear groundcrew, call for taxi.
When time to start Eng 2:
PNF actions all items from QRH 1-eng departure checklist
Yello HYD pump OFF,
APU Bleed ON,
Start Eng 2.
When start sequence finished, start timer (2min required before takeoff power)
APU bleed OFF,
APU OFF,
After start checklist.

Normal procedures follow from there (flying control check, takeoff briefing review, takeoff checklist etc.)

The rest of the pre-takeoff procedures usually take less than the 2 minute waiting period required between eng 2 start and takeoff.

To answer your specific questions:
- YES
- APU Bleed. You must be stopped to use crossbleed.
- during taxi
- PNF starts Eng 2 using the specific checklist. PNF can be CM1 or CM2 as we can taxy from either seat on the A320.

HTH
GL

[Sky Wave]

CY333

Imagine going to the holding point and you got a failure on the engine you just started and your MEL considers it as a NO GO item.

So you go back to stand. What's the big deal? With 200 aircraft they are more than happy to take a hit once in a while when balancing it against the potential savings.

Theres a reason to follow SOPs.........

It is easyjet SOP to consider using single engine taxi out whenever appropriate.

Dan Dare

Some very negative comments.

By not being ready at the holding point they loose opportunities to get airborne sometimes costing them 10 minutes or more holding.

The majority of pilots are conservative when it comes to starting the second engine. I've used the procedure on many occasions and have never yet missed an opportunity to get airborne. I'm sure the people in orange land will happily accept the odd missed departure in return for the potential savings.

If they break while starting at the head of the queue then there is no end of trouble getting them out and keeping movements going.

Not sure what you're saying here. Develop a fault or apply the brakes?

At a busy airport the wasted runway movement may not be made up until the end of the day - in effect every flight from the airport for the rest of the day is delayed by one orange aircraft not being ready.

BMI and many other operators use this procedure all of the time. The same would apply to any airline, not just the orange ones.

When pilots try to blag it and accept line-up clearance anyway with the expectation of being ready when cleared take-off (you wouldn't believe it, but some honestly think this is acceptable) the ensuing missed approach is fairly likely to also be oragne these days.

That would be unforgivable. I've never known it to happen.

When taxiing in and a tight turn in the wrong direction is required the taxyway is blocked (delaying another orange aircraft) while they re-start the other engine to enabble the turn.

We'll if it's only orange aircraft they're delaying, who cares? As I said, it takes judgment.

It's not everyones cup of tea and some Captains simply won't do it, however as greenfreddie has already said, the more you do it the less of a drama it is.

[MONSIEUR]

Thanks Gary and greefreddie.. Interesting stuff! Not yet allowed in my company . But who knows.. Fuel is, after all, our biggest expense. And I personnally wouldn't have a problem with it.
Cheers

[adamjoony]

3/4 engine taxi in has been SOP for QF 744s for about five years. That said, I did it only 3-4 times in my two years on the fleet as most times circumstances just don't permit it.

Single engine taxi out has been discussed a couple of times but I don't think QF is seriously considering it now that fuel costs have dropped considerably.

[Dave Clarke Fife]

Originally Posted by stevop21

bmi do this at LHR. I believe it isn't done on the first flight of the day, is that right?

Not correct stevop....as long as the engine gets the required warm up time ( 2 mins, 3 mins or 5 mins depending on type and how long since previous engine shut down) then the single engine taxi can be carried out be it the first or last flight of the day. Certain caveats such as weight, slope, surface conditions, LVP's and aircraft servicability have to be taken into consideration though.

[Gary Lager]

"depending on how long since engine shutdown"

- 1 eng taxi departure not allowed if engine has been shut down for >2 hrs (IAE engines) or >6 hrs (CFM)

[Dave Clarke Fife]

Originally Posted by Gary Lager

"depending on how long since engine shutdown"

- 1 eng taxi departure not allowed if engine has been shut down for >2 hrs (IAE engines)

Interesting Gary...............is that an orange SOP? Our blue Airbusaii with IAE donks can taxi single engine if shutdown >2hrs as long as the following from FCOM 3 04 90 is followed............................



– ENGINE 1 START
• After a shutdown period of more than two hours, to avoid thermal shock, the flightcrew should operate the engine at or near idle for at least five minutes before advancing the thrust lever to high power. Taxi time may be included in the warm up period.

[Akrapovic]

Well done Sky Wave for taking the time to respond to some somewhat moronic assumptions.

We are paid to make decisions every day and single-engine taxi out, and judging when to start that engine as a balance between saving fuel and meeting warm-up criteria, is just one of those calls we are encouraged to make. The word being 'encouraged'. It's not compulsory, but I am a fan of it. I wasn't at first, but just like Sky Wave mentions, the more you do it, the more it becomes the norm.

I've never had to turn down a line-up clearance as a result of getting it wrong, nor caused anyone to go-around as I'm starting an engine up on the runway :roll eyes: - it just doesn't happen.

Many airlines do this, it is certainly not exclusive to easyJet. It's also worth remembering that the fuel you save taxiing on one engine, is fuel for YOU when you get airborne. Single engine taxi on arrival is for the company and keeps you in a job, single engine departure is for you and keeps you in the air . . . .thats how I see it, and therefore it makes sense to do it.

[Dave Clarke Fife]

By not being ready at the holding point they loose opportunities to get airborne sometimes costing them 10 minutes or more holding.

At LHR we advise ATC when requesting our PDC or on first contact with delivery that we intend to taxi out single engine. A little reminder to ground when calling for taxi usually means that when we go over and monitor tower the controller will 9 times out of 10 advise us of how many minutes we can expect until it's our turn. Most guys are cautious and will actually have No2 up and running earlier than this advisory time.

[Gary Lager]

Yep Dave, orange SOP. Not sure how many IAE-d jets we have (inherited from GB), and I've never flown one with this lot so not sure if there isn't a proviso like yours though.

[Dan Dare]

Today 4 aircrcaft were not ready at a busy summertime hold when I was on tower. They do not always say "sorry, I ed up and didn't start the engines in time", but as taxy time today was about 30 minutes it sems unlikely to have been the other favouites of no (centrally prepared and slower in the summer) figures or insecure cabin. Three of the four were orange. Okay, sometimes I can get someone past and not lose the runway capacity, but sometimes I can't. If I lose a movement it is unlikely to be made up until the end of the day. EVERY subsequent aircraft that day will experience a delay as a result. My customer (the airport) will not be best pleased by this because they can't plan on the runway utilisation otherwise possible, but surely all the subsequently delayed company aircraft also counteract any cost savings from this behaviour. Incidentally, the difference between being ready at an intersection when the opportunity exists to make use of your favourable SID and joining the back of the queue at the holding point could be 20 minutes. When aircraft are not ready when I need them to be I often log their delay and it usually makes more than 4-6 minutes difference.

[greenfreddie]

As has been said in a number of earlier posts on this thread, there is a tendancy to ensure both engines are running earlier than strictly necessary to avoid being embarassed by not being ready on time, and 30 minute taxi times would more than justify using the procedure.

Maybe working a little give and take into your approach to liaising with the jets would be helpful - at the end of the day, nobody screws up on purpose, and we (ought to) understand that everybody is working hard within their own corner of the operation. A friendly "for planning, can you accept [intersection]" would go a long way to ensuring crews can quickly give you what you're asking for - I doubt anybody is going to get worked up if they end up getting full length, and as you say, the gamble of a few extra minutes at idle against knocking 10 minutes off the delay would be taken by everyone I know.

It isn't just the engines that constrain these requests either: If the performance figures need to be recalculated, it will take time to plug the data into the laptop, copy into the FMGC and cross check, and there might be issues in the cabin - after 30 minutes of taxi, and probably another 30 minutes of queueing and boarding, calls of nature may result in the cabin not being secure for takeoff.....we don't just ferry nice docile and compliant people round the skies you know.

Jus in case you take this as a snipe at our friends in the tower, the service we get where I live is fantastic and I've been helped out a number of times with a bit of intersection 'queue jumping' when I've let them know we've been tight on duty limits, so it does work both ways

[Sky Wave]

Well, I managed 2 single engine taxi outs at LGW yesterday without screwing up. I'm sure there were many many more aircraft that used the procedure since we were on 08R, therefore 4 aircraft failing to accept a line up is not bad odds. (Assuming you're referring to LGW) As greenfreddie noted those that couldn't accept may of had cabin problems or perhaps didn't have intersection figures.

Perhaps if you look for solutions to the problem rather than just berating us it may help. You've stated that taxi times were 30 minutes. That means any aircraft that started both engines together were pissing away fuel for 25 minutes for no good reason.

It takes about 4 minutes to start the second engine and get the checks done. It's usually obvious when you need to start the engine as you can see how many aircraft are in front of you on your section of taxiway.

The only time that i would think people could get caught out is if they have a long slot which subsequently comes forward. When I've been in this situation I've advised the tower that we only had one engine running and they called us as soon as the slot disappeared to tell us to start our engine. Worked like a dream and not exactly rocket science.

SW