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Delta - Taxiing On One Engine, Is This New?  
User currently offline9V-SPJ From United States of America, joined Dec 2000, 752 posts, RR: 0
Posted (9 years 9 months 2 weeks 16 hours ago) and read 10314 times:

Hi everyone
I recently flew delta about 4x - ATL-JFK, JFK-CVG, CVG-ATL and most recently ATL-LAX. I noticed that on every single flight, the crew taxi on one engine, and when they near the departure runway, the second engine is started up. Same happens right after landing, one engine is shut down while the other is used to taxi with. Is this a fuel saving move? When did they start this practice? Also, I flew home to LA on DL603, a B762, and I noticed that while taxing on one engine, the crew had to use a significant amount of power to keep us moving. Is he saving fuel in the long run?
Just found this to be a bit odd.

9V-SPJ

60 replies: All unread, showing first 25:
 
User currently onlineWesternA318 From United States of America, joined Oct 2004, 5675 posts, RR: 23
Reply 1, posted (9 years 9 months 2 weeks 16 hours ago) and read 10258 times:

Probably trying to save some gallons for the trip home, lol.


Check out my blog at fl310travel.blogspot.com!
User currently offlineNgr From United States of America, joined Apr 2001, 176 posts, RR: 0
Reply 2, posted (9 years 9 months 2 weeks 16 hours ago) and read 10244 times:

I noticed the same thing when I flew on Delta over Thanksgiving. I flew BHM-ATL-CAE and CAE-ATL-BHM on MD-88s and 737-200s, and on 3 of the 4 flights we taxied on 1 engine. I wondered the same thing about fuel saving, because when until the 2nd engine was started, the pilot used a lot more thrust than I am accumstomed to. I flew on Delta in August and they taxied on both engines for all flights.

User currently offlineAzul320 From United States of America, joined Jun 2004, 281 posts, RR: 0
Reply 3, posted (9 years 9 months 2 weeks 16 hours ago) and read 10232 times:

Ugh...read this...
http://aviationnow.com/avnow/news/channel_awst_story.jsp?id=news/12064top.xml



Excuse me, while I kiss the sky
User currently offlineGo3Team From United States of America, joined Mar 2004, 3267 posts, RR: 16
Reply 4, posted (9 years 9 months 2 weeks 15 hours ago) and read 10207 times:

I wonder if that DL LGA fuel emergency a few weeks ago is related to this.


Yay Pudding!
User currently offlineLH423 From Canada, joined Jul 1999, 6501 posts, RR: 54
Reply 5, posted (9 years 9 months 2 weeks 15 hours ago) and read 10206 times:

I noticed this as well on my last AA flight, BOS-FLL. I didn't even notice until we were getting to the end of the take-off queue and then I heard the other engine start up. I thought that it was awfully quiet considering we were sitting in row 28 on an MD-80.

LH423



« On ne voit bien qu'avec le cœur. L'essentiel est invisible pour les yeux » Antoine de Saint-Exupéry
User currently offlineN506CR From Costa Rica, joined Nov 2004, 147 posts, RR: 2
Reply 6, posted (9 years 9 months 2 weeks 15 hours ago) and read 10167 times:

Azul320

great article! thanks for sharing!  Big thumbs up

.:capt_moralesg:.


User currently onlineWesternA318 From United States of America, joined Oct 2004, 5675 posts, RR: 23
Reply 7, posted (9 years 9 months 2 weeks 15 hours ago) and read 10165 times:

"Continental's $112-per-flight savings on its Houston-Cancun route is part of an initiative aimed at saving $8 million a year by purchasing extra fuel at lower cost airports."

Hrmm...you think they may be running a scenario of chanign hubs to one with lower avgas? LOL. Instead of IAH or EWR, how bout...SLC and CLE?



Check out my blog at fl310travel.blogspot.com!
User currently offlineJuanchie From United States of America, joined Jan 2004, 190 posts, RR: 0
Reply 8, posted (9 years 9 months 2 weeks 15 hours ago) and read 10133 times:

Let's also keep in mind this has another benefit. By taxining on one engine, you save on engine rotations. In the long run, the engines will last longer and there is no need to run two engines when one will do.


Juanchie



God, forgive me for who I am, and help me be the man I want to be.
User currently offlineFlyibaby From United States of America, joined Aug 2004, 1017 posts, RR: 6
Reply 9, posted (9 years 9 months 2 weeks 15 hours ago) and read 10042 times:

I'm pretty sure that all airlines are doing this now, even the APU useage. The exception is with SW probably because their pilots fly down the taxiway. I used to think it was to be ontime or to give their ramp crews extra time to turn the aircraft, but then I found out it was because the pilots are only paid by how long the trip is scheduled, not how long it takes them. So by taxiing fast they can try and stay below their hours per month and pick up a few additional trips per month.

User currently offlineFlyibaby From United States of America, joined Aug 2004, 1017 posts, RR: 6
Reply 10, posted (9 years 9 months 2 weeks 15 hours ago) and read 10030 times:

I forgot to mention, Independence did a study on this, and found that it costs $1 a minute to run the APU instead of groundpower while parked at the gate. With an engine turning on the ground, about $5 a minute. Therefore the costs savings, and this is just based on the CRJ.

User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 11, posted (9 years 9 months 2 weeks 14 hours ago) and read 9994 times:

I'm somewhat surprised they're doing this again.


DC10s used to be taxied out on two engines at UA/AA/CO, with #2 engine started slightly before takeoff.

It was later found that this wore the hell out of #2 engines, with maintenance costs that nearly erradicated any fuel savings.



(though, before anyone asks, this was not cited as a contributing factor to the #2 failure in UA232)


User currently offlinePlanesarecool From United Kingdom, joined Nov 2001, 4124 posts, RR: 11
Reply 12, posted (9 years 9 months 2 weeks 14 hours ago) and read 9992 times:

I wondered why the Delta B767 i saw at Gatwick today was taxiing on one engine, and then when it got to the holding point, there was a kind of hum. It must have been the other starting up.

-Stephen


User currently offlineAtrude777 From United States of America, joined Aug 2003, 5692 posts, RR: 52
Reply 13, posted (9 years 9 months 2 weeks 14 hours ago) and read 9940 times:

This engine cutting process ting did start with Delta Express, when they were using Boeing 732's. A pilot noticed how unneccesary it was to use both engines. They were trying to figure out ways to turn arund faster. So they decided as soon as the 732 landed they would switch the right engine off, and taxi on the left so when they got to the gate the ground people could immediatly go to the plane and start taking the bags off without having to wait for the engine to stop for fear of being sucked in. They saw how much time this saved so Delta decided to try it out to the rest of the fleets. Then other airlines caught on. One would think this would be something WN thought of, but as someone pointed out it doesnt benefit them.

Alex



Good things come to those who wait, better things come to those who go AFTER it!
User currently offlineDr.DTW From United States of America, joined May 2000, 290 posts, RR: 1
Reply 14, posted (9 years 9 months 2 weeks 13 hours ago) and read 9875 times:

Funny, I was going to post this very same topic.

I noticed a one engine taxi on a 763 on DL from ATL-MIA last month.

IMPORTANT QUESTION: How can a plane taxi with assymetric thrust??

Dr.DTW


User currently offlineAirxLiban From Lebanon, joined Oct 2003, 4512 posts, RR: 53
Reply 15, posted (9 years 9 months 2 weeks 13 hours ago) and read 9854 times:

just came off an AA MD-80 yesterday in fact where we taxiied on one engine.

i actually didn't realize it, until the pilot said we are number 3 in line for takeoff, there is a UA 752 that is also heading to los angeles in front of us.

in the meantime, we're going to be starting up the other engine and taking off for los angeles.

well whatever it didn't sound exactly like that, but the point was that we were taxiing on one engine.



PARIS, FRANCE...THE BEIRUT OF EUROPE.
User currently offline57AZ From United States of America, joined Nov 2004, 2550 posts, RR: 2
Reply 16, posted (9 years 9 months 2 weeks 13 hours ago) and read 9844 times:

The amount of thrust required to taxi is low enough that there is no difference in handling characteristics. Older jet aircraft often taxied on one or two engines but the procedure specified which engine could be used due to design limitations. I believe that the modern systems on twins can usually be driven by either engine. However, on older jets that usually was not the case.


"When a man runs on railroads over half of his lifetime he is fit for nothing else-and at times he don't know that."
User currently offlineOttoPylit From , joined Dec 1969, posts, RR:
Reply 17, posted (9 years 9 months 2 weeks 13 hours ago) and read 9764 times:

Atrude777 has it correct. During the mid-90's, Delta asked employees for suggestions in saving money. Pilots suggested that taxiing in on one engine, then taxiing out on the other would save time, but also keep the time on each engine the same. It worked and I assume for the most part is still used successfully. It really doesn't take that much more power to get the plane moving and any more that is used can be backed off once the plane's inertia is pushing the plane along.

Also, when it comes to taxiing a plane, as long as its at slow speeds, the assymetric thrust won't affect the plane any. It's only at higher speeds will the thrust start to interfere with the planes movement.


User currently offlineDL Widget Head From United States of America, joined Apr 2000, 2094 posts, RR: 5
Reply 18, posted (9 years 9 months 2 weeks 12 hours ago) and read 9719 times:

Nope, it's not new. DL has been doing this for years as it really does save on fuel expenses.

User currently offlineCrosswind From United Kingdom, joined Nov 2000, 2598 posts, RR: 58
Reply 19, posted (9 years 9 months 2 weeks 12 hours ago) and read 9696 times:
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We evaluated taxiing one one engine last year, with mixed results;

For the A320/321 fleet this became an approved procedure after landing only, saving both fuel and brake wear, as the A320/321 have quite a lot of residual thrust at idle so braking is required with both engines running to keep the aircraft at a safe taxi speed.

For the B757/767 fleet it was rejected. The heavier weights of these aircraft meant that you need to apply a fair amount of thrust on the live engine break away from a standstill, and more thrust than normal to keep the plane moving, negating any other savings you might make. Also the GE-CF6 on the B767 requires a 5 min reccomended cooldown period after landing before shutdown.

It was felt undesirable to delay engine startup on departure for any aircraft in the fleet. Starting all engines on pushback provides some degree of warmup, and also problems that can occur after startup may not always be apparent to the crew, and may not become so until the aircraft has commenced it's takeoff run. For example a fuel leak from within the engine would be reported by your pushback crew, but if you start that same engine at the holding point, there may well be nobody to see it...

Just one operator's experience.

Regards
CROSSWIND


User currently offlineAV8AJET From United States of America, joined Sep 2003, 1348 posts, RR: 1
Reply 20, posted (9 years 9 months 2 weeks 12 hours ago) and read 9698 times:

We even taxi on one engine at ASA in DFW & ATL especially due to the long taxi time and long lines. We do it when we can, not only does it save fuel but also slows the taxi speed down so you don't have to "ride" the brakes.

IMPORTANT QUESTION: How can a plane taxi with asymmetric thrust??

Power steering helps overcome this, no big deal really.



"To fly or not to fly there is no question!"
User currently offlineUN_B732 From United States of America, joined Jul 2001, 4289 posts, RR: 4
Reply 21, posted (9 years 9 months 2 weeks 12 hours ago) and read 9671 times:

I think jetBlue has done this for a while, but I didn't feel it.
-Mr. X



What now?
User currently offline9V-SPJ From United States of America, joined Dec 2000, 752 posts, RR: 0
Reply 22, posted (9 years 9 months 2 weeks 12 hours ago) and read 9664 times:

Thanks for the replies! Are there certain aircraft in DL's fleet where they taxi on one engine? Does it also depend on the taxi weight of the aircraft?

9V-SPJ


User currently onlineWesternA318 From United States of America, joined Oct 2004, 5675 posts, RR: 23
Reply 23, posted (9 years 9 months 2 weeks 9 hours ago) and read 9491 times:

Can anyone tell me if the beloved ex-WA 733's taxi with one turning and one umm...sitting?


Check out my blog at fl310travel.blogspot.com!
User currently offlineISP From United States of America, joined Sep 2004, 101 posts, RR: 0
Reply 24, posted (9 years 9 months 2 weeks 9 hours ago) and read 9474 times:

JetBlue began doing this Monday 11/29. Also, they are now using GPU's when they never did in the past.

US Airways also taxies on one engine on most of my flights recently.


25 Post contains images FriendlySkies : On a flight from ATL-ORD on an A319, the pilot used only one engine before takeoff AND after landing. Before hand, we had to sit in the penalty box fo
26 ACAfan : Related Question: How much cheaper is a pushback vs. a powerback?
27 PlaneSmart : Fuel prices may have brought this into focus for some airlines, but it's not a new practice. In addition to saving fuel, some airlines lease the airfr
28 Ckfred : I think airlines have been experimenting with ways to save fuel since the oil embargo of 1973. A friend of mine used to fly 727s for AA between 1989 a
29 TrnsWrld : Pretty good thread here. I will first say that this procedure is nothing new. I have been flying for many many years and I have experienced this uncou
30 Post contains images CPDC10-30 : Doing this would be terrible with an A32x series aircraft, lucky Delta doesn't have any. First the high pitched drilling sound and then the barking no
31 AAplatnumflier : Actually it is one of the cost cutting proposals AA and DL passed to save money on fuel. It was a good idea. Along with that they reduced the amount o
32 Greaser : So do 747/340s taxi with 2 or 3or 4 engines, because all of the 747s i have flown on have taxied on all 4.
33 AirxLiban : crosswind, what company are you with? not BA i assume...
34 N743AS : Personally, I'm all about getting to altitude and shutting one down...I found it's a little quieter and fuel burn is reduced. However we do slow a lit
35 Fiedman : I know turboprops doing a lot I see it a lot with the Dash-8's they taxi in on one engine and feather the second one. And on and off topic maybe someo
36 Angelairways : At last people are learning to be efficient and stop wasting. Hurrah for high fuel prices!
37 Leskova : I've experienced the same here in Europe and in South Africa as well - at least after landing... Angelairways, you're right about that - now let's hop
38 PlaneSmart : Fiedman I know turboprops doing a lot I see it a lot with the Dash-8's they taxi in on one engine and feather the second one. They feather the port en
39 Leskova : And on and off topic maybe someone can either confirm this or correct it but don't four engin airliners shut down one engin enroute to conserve fuel i
40 Silver1SWA : I'm pretty sure that all airlines are doing this now, even the APU useage. The exception is with SW probably because their pilots fly down the taxiway
41 PlaneSmart : There's no way an engine would / should be shutdown in flight, other than for safety reasons. Depending on weight & wind conditions (& timetable / slo
42 Deltacvg : ..when Taxing up to the gate, DL 757's almost exclusively taxi in on the #2 (F/O's side) engine. -Beat Army
43 Dazed767 : I thought I was losing my mind a few times, but I've been on a lot of flights where they did this. USAir for one, every flight I was on with them they
44 57AZ : I don't know whether the airlines powerback/shutdown in-flight for fuel/engine conservation. The United States Navy does do this as standard procedure
45 FriendlySkies : And on and off topic maybe someone can either confirm this or correct it but don't four engin airliners shut down one engin enroute to conserve fuel i
46 Santhosh : Is there really a big difference in fuel consumption when taxing with one engine rather than 2 engines? Also even if one engine is used for taxing the
47 9V-SPJ : Santhosh, thats what I was wondering as well. But I think that in the long run, it does save money. I think someone mentioned that power steering is a
48 Mm320cap : FriendlySkies, Sorry this is so far down below your post, haven't been on the forum in awhile. The reason you hear a high pitched whine on the A319/32
49 Pilotpip : Jet engines at idle aren't very efficient. They are still at about 60% max thrust and sitting at a lower altitude so the consumption can still be thou
50 Sacflyer : I have to say, IMHO, that the slant of the article missed the point just a little. This is not a fuel issue; it is a money issue. 1) The cost of fuel
51 Pilotpip : Sacflier, While GSE adds more equipment to maintain, it doesn't require an A&P and I'm sure you can find a mechanic off the street that can handle tha
52 Sacflyer : Pilotpip, Agreed! I may have rambled off my point a bit, which was that this is a Direct Operating Cost issue and not just a fuel issue. Not running a
53 BR715-A1-30 : I also noticed this on my recent AirTran flights... The pilot did not start the APU until it was time to leave... I could hear it whining and coughing
54 Modesto2 : Mm320cap, interesting you mention the PTU. On a JetBlue JFK late afternoon departure, we taxied on one engine while waiting 45 minutes through the tak
55 PSU.DTW.SCE : NW does not do taxi on one engine Mesaba did this for a while, but has since returned to taxing on 2 engines US taxis on one engine. NW does not norma
56 GuitrThree : Pilotpip: Assuming 1000 pounds per hour at idle, a 10 minute taxi will save about 170 pounds of fuel. That's a little over 10 gallons. Jet-A weighs 17
57 Pilotpip : Jeez. How did I do that one? Should I admit that I'm a fueler? I was too busy patting myself on the back to realize that I made that mistake. Thanks.
58 GuitrThree : Pilotpip, no problem, I figured that was a little off.... but if you are a fueler, I might just pull up in my 172 one day and tell you to "gimme some
59 Ual747 : In 1998 I flew DFW-LGW on a BA DC-10. The 2nd engine was started right before take off. Other than that, I can't remember taxiing on any aircraft besi
60 VgnAtl747 : I work for a Comair station, and we frequently see this also. We get a lot of pilots that taxi out on only engine #1, then start #2 just prior to t/o.
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