A-320 Single Engine Taxi out Myth Busters
08-06-2010, 04:16 PM
#101
Gets Weekends Off
Joined APC: Jun 2009
Posts: 5,113
...you seem to have a very hard time comprehending the fundamental differences between DAL and AA management. You see, DAL management takes it upon itself to go out of their way in promoting harmony within the pilot corps. This encourages the pilot group to step up to the plate in furthering pilot-management relations.
It's only through the bankruptcy process, when we started forcing our way into discussions among the board, and between the board and investors, and only through the emergence of a common enemy (Doug Parker), did we see some interests aligned. At that time, management concluded it would be less expensive to work a little with us, rather than completely overtly against us. It was a combination of smarter tactics on our part, and the realization this pig would never fly again without us.
The main difference between us, in terms of walking in the other's shoes, is that you didn't go through bankruptcy, and in the respective tactics of our unions. As far as any other romantic notions about us being treated kindly by an altruistic management... they are but an soft illusion barely disguising a fragile truce.
08-06-2010, 04:42 PM
#103
Gets Weekends Off
Joined APC: Oct 2007
Posts: 125
A well-done post regarding S/E taxi.
At my airline, we try to S/E taxi whenever possible on the 737 fleet. Sometimes the stars just don't align (hot asphalt, high elevation, whatever). I'm sure it saves a lot of fuel in the long term.
However, one oversight in your gathered statistics. You failed to calculate the difference of power used in 1 engine vs. 2 engines. I know I'm splitting hairs, but it would be interesting to see that number.
Example: 2 engines take less power each than 1 engine (say average 32% N1 for two, versus 40% while on one). How much more fuel burn are you using on the 1 engine compared to the individual burns of two engines?
If you run one engine harder to taxi, PLUS the APU's respective fuel burn, how much less is that than just running two engines?
Clear as mud?
At my airline, we try to S/E taxi whenever possible on the 737 fleet. Sometimes the stars just don't align (hot asphalt, high elevation, whatever). I'm sure it saves a lot of fuel in the long term.
However, one oversight in your gathered statistics. You failed to calculate the difference of power used in 1 engine vs. 2 engines. I know I'm splitting hairs, but it would be interesting to see that number.
Example: 2 engines take less power each than 1 engine (say average 32% N1 for two, versus 40% while on one). How much more fuel burn are you using on the 1 engine compared to the individual burns of two engines?
If you run one engine harder to taxi, PLUS the APU's respective fuel burn, how much less is that than just running two engines?
Clear as mud?
08-06-2010, 05:13 PM
#104
Gets Weekends Off
Joined APC: Jun 2009
Posts: 5,113
I meant smarter tactics on our part... But once we made ourselves more relevant, we did find one or two executives willing to work something out. It does take two to tango.
08-06-2010, 06:16 PM
#105
Gets Weekends Off
Thread Starter
Joined APC: Feb 2006
Position: A320 CA
Posts: 973
A well-done post regarding S/E taxi.
At my airline, we try to S/E taxi whenever possible on the 737 fleet. Sometimes the stars just don't align (hot asphalt, high elevation, whatever). I'm sure it saves a lot of fuel in the long term.
However, one oversight in your gathered statistics. You failed to calculate the difference of power used in 1 engine vs. 2 engines. I know I'm splitting hairs, but it would be interesting to see that number.
Example: 2 engines take less power each than 1 engine (say average 32% N1 for two, versus 40% while on one). How much more fuel burn are you using on the 1 engine compared to the individual burns of two engines?
If you run one engine harder to taxi, PLUS the APU's respective fuel burn, how much less is that than just running two engines?
Clear as mud?
At my airline, we try to S/E taxi whenever possible on the 737 fleet. Sometimes the stars just don't align (hot asphalt, high elevation, whatever). I'm sure it saves a lot of fuel in the long term.
However, one oversight in your gathered statistics. You failed to calculate the difference of power used in 1 engine vs. 2 engines. I know I'm splitting hairs, but it would be interesting to see that number.
Example: 2 engines take less power each than 1 engine (say average 32% N1 for two, versus 40% while on one). How much more fuel burn are you using on the 1 engine compared to the individual burns of two engines?
If you run one engine harder to taxi, PLUS the APU's respective fuel burn, how much less is that than just running two engines?
Clear as mud?
I have a spreadsheet i could post, but every time I try to copy and paste into the thread it displays all crazy
If anyone could PM me and tell me how to post or upload a file I could display the actual recordings and actual fuel savings....data that even the data lovers would love
08-06-2010, 10:16 PM
#106
Gets Weekends Off
Joined APC: Nov 2008
Position: A330B
Posts: 102
Just get with the program
OK... So now we've heard that Jet Blue, Spirit, US Air, and UAL all SE taxi A320 series aircraft upwards of 90% of the time. I'll throw in Frontier (as I used to fly there). F9 SE taxied 100% of the time with crossbleed starts.
Come on guys... last time I checked DAL was the single largest Airbus operator. The least we could do is operate efficiently.
Come on guys... last time I checked DAL was the single largest Airbus operator. The least we could do is operate efficiently.
08-07-2010, 05:09 AM
#107
No longer cares
Joined APC: Mar 2008
Position: 767er Captain
Posts: 12,109
You're comparing fighting a contract battle at an airline with raising kids? You must not have any. Heeeeeere's yer sign.
I can't wait to hear your pro-company stance if/when DL someday decides to play hardball with you guys over contract negotiations. I'm sure you'll gain an industry leading contract with all your single engine taxi and koolaid drinking antics.
It's a whole different world when you're not sitting at the top, my friend. Hard earned contract gains are NOT achieved through singing kumbaya, they are earned through getting what you negotiate. Throw in a determined union-busting management and you have the recipe for FUPM-stew. You have to play hardball with them, because that's what they do with us. And if we give an inch, they take a mile. You Deltoids have never had to worry about that with your Southern-friendly company.
I'd just like you to put yourself in our shoes. Richard Anderson begs for concessions to save the company. You all agree, take one for the team, and take upwards of 30% pay cuts - some more, due to forced downgrades. The very next day, Anderson announces a multimillion dollar retirement plan for the top 100 executives, all the while preaching "Pull together, win together." Every year, the top 100 are also awarded millions in bonuses - REGARDLESS whether the Company is profitable or not. The Flight Dep't engages in a sick-time jihad, sending threatening Fedex letters to anyone who calls in sick more than 5 times a year. Flight supervisors flying a trip whip out their cell phones and try and bust a slow-taxiing pilot (going slow due to a gate being occupied) while on an active taxiway. The pilot is removed a whole month without pay. The airline continues to shrink, parking dozens of jets while the competition grows. CA upgrades are upwards of 18 years - junior CA is a 1991 hire. Richard Anderson tells Wall Street that he's an industry follower, not a leader, and is more interested in forging alliances than growing his own airline. Wall Street asks him "Is that all you got? " (translated: Pull your head out of your ass.) The Company keeps 1800 pilots on the street, then announces yet another furlough of 70 pilots, despite the fact that crew scheduling is BEGGING for pilots, reserves flying 85 hours every month and lineholders are getting reassigned. But the company can't recall, no, that would be a show of weakness to the pilots during contract negotiations - you know, the whole hostage concept. A volcano blows in Europe, and crews who had a nice 75 hour month are now suddenly dropped down to the 64 hour guarantee, and the Co will not make up the difference - tough luck, you're on your own.
I could go on...
and on...
and on...
... but that, in a nutshell, is why we don't do the company any favors.
You guys live in a different world. Enjoy it while it lasts.
I can't wait to hear your pro-company stance if/when DL someday decides to play hardball with you guys over contract negotiations. I'm sure you'll gain an industry leading contract with all your single engine taxi and koolaid drinking antics.
It's a whole different world when you're not sitting at the top, my friend. Hard earned contract gains are NOT achieved through singing kumbaya, they are earned through getting what you negotiate. Throw in a determined union-busting management and you have the recipe for FUPM-stew. You have to play hardball with them, because that's what they do with us. And if we give an inch, they take a mile. You Deltoids have never had to worry about that with your Southern-friendly company.
I'd just like you to put yourself in our shoes. Richard Anderson begs for concessions to save the company. You all agree, take one for the team, and take upwards of 30% pay cuts - some more, due to forced downgrades. The very next day, Anderson announces a multimillion dollar retirement plan for the top 100 executives, all the while preaching "Pull together, win together." Every year, the top 100 are also awarded millions in bonuses - REGARDLESS whether the Company is profitable or not. The Flight Dep't engages in a sick-time jihad, sending threatening Fedex letters to anyone who calls in sick more than 5 times a year. Flight supervisors flying a trip whip out their cell phones and try and bust a slow-taxiing pilot (going slow due to a gate being occupied) while on an active taxiway. The pilot is removed a whole month without pay. The airline continues to shrink, parking dozens of jets while the competition grows. CA upgrades are upwards of 18 years - junior CA is a 1991 hire. Richard Anderson tells Wall Street that he's an industry follower, not a leader, and is more interested in forging alliances than growing his own airline. Wall Street asks him "Is that all you got? " (translated: Pull your head out of your ass.) The Company keeps 1800 pilots on the street, then announces yet another furlough of 70 pilots, despite the fact that crew scheduling is BEGGING for pilots, reserves flying 85 hours every month and lineholders are getting reassigned. But the company can't recall, no, that would be a show of weakness to the pilots during contract negotiations - you know, the whole hostage concept. A volcano blows in Europe, and crews who had a nice 75 hour month are now suddenly dropped down to the 64 hour guarantee, and the Co will not make up the difference - tough luck, you're on your own.
I could go on...
and on...
and on...
... but that, in a nutshell, is why we don't do the company any favors.
You guys live in a different world. Enjoy it while it lasts.
Wow!! Just an amazing lack of situational awareness of those around you.
08-07-2010, 05:55 AM
#108
Gets Weekends Off
Joined APC: May 2008
Posts: 879
reddog,
Is there any data to support the actual savings of fuel at the heavier weights? Is there a published report where two planes at identical weights travel the same taxi route and show the difference between fuel used? What I see in ATL during my commutes is a lot of high power settings during breakaway, acceleration and during uphill taxi segments. Then there's the high power settings during crossbleed start. I've never seen an actual side by side comparison.
Carl
Is there any data to support the actual savings of fuel at the heavier weights? Is there a published report where two planes at identical weights travel the same taxi route and show the difference between fuel used? What I see in ATL during my commutes is a lot of high power settings during breakaway, acceleration and during uphill taxi segments. Then there's the high power settings during crossbleed start. I've never seen an actual side by side comparison.
Carl
Regards crossbleed starts, a well-executed crossbleed start burns about 4 lbs of fuel (45 seconds with an increase of about 400pph). The APU burns about 5 lbs per minute with an air load, so it doesn't take a whole lot of saved APU run time to offset the crossbleed.
Last edited by FAULTPUSH; 08-07-2010 at 06:39 AM.
08-23-2015, 10:56 PM
#109
New Hire
Joined APC: Aug 2015
Posts: 1
MYTH BUSTERS-SINGLE ENGINE (SE) TAXI
This article may well have been titled; “Confessions of a start em both up captain”. I’ll be the first to admit that my use of SE taxi had been less than optimum in the past. A recent email from Captain Glen Fink stated that the A-320 fleet was performing less than 10% of SE taxi outs.
I decided to take a look at my own operation during the month of June, and see if it was possible to increase my use of SE taxi out. I was determined to increase my SE taxi out, though honestly, I didn’t think it was possible due to some well held beliefs, or myths. It seems that the A320 pilots hold a paradigm which does not embrace SE taxi. I set out to debunk the no SE taxi myths. Let’s take a look at some of those myths.
I DON’T WANT TO LOAD UP MY FIRST OFFICER WITH A SINGLE ENGINE TAXI; START EM BOTH UP! BUSTED In the past this may have been a reasonable CRM concern. Delta North aircraft would often receive their ‘numbers’ late in the taxi. However with the cutover to the Delta AWABS/WDR we now receive our numbers at the gate. As Captain, you will need to adjust the second engine start to your F/Os comfort level. As the F/O becomes more comfortable with the delayed engine start you can increase the amount of SE taxi time. Almost every F/O that flew with me during June was initially uncomfortable with the delayed engine start. Surprising? No. If only 10% of F/Os were getting landings I’d bet they’d be uncomfortable with landings too. By the end of the trip, SE flow was a standard routine.
IT’S THE FIRST FLIGHT OF THE DAY; START EM BOTH UP. BUSTED During June seven of my flights were first flights of the day (30%). Though the requirement to have 5 minutes of warm-up time limited the amount of SE taxi I was surprised at how many minutes of SE taxi I had actually performed. Even at SMF with a short taxi we recorded 4 minutes of SE taxi.
**Least SE taxi out time for first flights of the day; 3 min, Highest SE taxi out; 6 min, avg SE taxi out 4.6 min**
WE ARE TOO HEAVY FOR SINGLE ENGINE TAXI; START EM BOTH UP BUSTED My weights varied from 128.7 to 165.0 pounds. On all but one flight at max takeoff weight I was able to SE taxi. Some factors for considerations in a successful SE taxi out included concrete vs blacktop. Direction of turn on taxi out (right turns more reasonable N1s than left turns) For example, in the alley at LGA you may need to start both for the initial taxi, then shut one down following the required cool down. Heavy SE taxi requires planning. For example taxi to Rwy 4 at LGA not a problem…crossing Rwy 4 taxi to 13 at taxiway ‘F’ may require an early 2nd engine start.
**Lowest SE taxi out weight;128.7 lbs Highest SE taxi out weight;163.4 lbs. Average SE taxi out weight; 146.1 lbs**
ANY WEIGHTS GREATER THAN MAX LANDING WEIGHT WILL REQUIRE EXCESSIVE N1s; START EM BOTH UP. BUSTED This myth may have developed life during the FNWA Vol 1 days (along with max N1s) See the accompanying spread sheet. The average N1 for breakaway was 32.5%. Again planning ahead will mitigate the impact of breakaway thrust. Have the push crew turn your tail during the push back so that you don’t need to turn into engine 1. If unable to do that, ask for a deeper push than normal to allow forward taxi prior to turning. Carry the thrust into the turn etc. Know where your tail is pointing Is 45% N1 breakaway a big deal if your tail is clear of personnel and carts/equipment? Max N1 breakaway was experienced at LAX (161,300 lbs) at the top of the alley; 48%. Tail was clear of personnel with no objects behind the jet An interesting observation here is that we had a heavier taxi out weight of 163,400 in CVG with only a 37% N1 breakaway. The difference?; Concrete and slight downhill. Plenty of variables affect SE taxi at heavy weights. The key take away is, don’t summarily rule out SE taxi simply based on weight.
**Lowest breakaway 20% N1, highest breakaway 48% N1, Average breakaway 32.5% N1**
I’LL ONLY SAVE A FEW MINUTES, IT’S NOT WORTH THE HASSLE; START EM BOTH UP BUSTED Probably the biggest myth of all. It’s been said before, but it needs to be repeated; the cumulative savings of SE taxi adds up. With the number of flights we operate a day, you and I can make a significant impact in fuel cost savings. What savings did one Captain achieve in June?
**In 20 flights utilizing SE taxi, a total of 143 minutes of SE taxi was recorded.( average SE taxi out was 7.15 minutes!) **
**Total SE taxi fuel saved 2,280 lbs.**
**APU burn during SE taxi: 715 lbs (5 lbs/min)**
**Net SE taxi fuel saved: 1,565 lbs ( 226.8 gallons)**
If you’ve stayed with me so far, thanks. So what‘s the way ahead? First of all, let’s make SE taxi a conscious decision in your flight planning. No different than preflight/taxi/take off/climb out/ cruise/ descent/ approach / landing/ and taxi-in.
I can already hear the howls…………They don’t have park crew waiting for us…They don’t have ext pwr waiting for us….They have us carry too much fuel….Yes, Yes and Yes. However, these are things you as a crew have little control over. Where you have a direct impact on fuel savings however is determining when you start the second engine!
My personal wish list? I’d like to see the cross bleed procedure revisited. Currently the A-320 requires the parking brake set for cross bleed start making that option impractical in most SE taxi scenarios. My data shows that if the APU could have been shut down, and cross bleed utilized for the second engine start an additional 715 pounds of fuel would have been saved.
If you’re still with me great…you may be asking; ‘OK, so what’s in it for me?’ Think job security.
Captains, your next upgrade may be impacted by higher operational costs, but your junior First Officers will be the first to be negatively impacted by higher operational costs. First Officers, become proactive in the single engine start discussion. Captains, I ask you to challenge yourself and increase your SE taxi time
We can do better, we must do better.
This article may well have been titled; “Confessions of a start em both up captain”. I’ll be the first to admit that my use of SE taxi had been less than optimum in the past. A recent email from Captain Glen Fink stated that the A-320 fleet was performing less than 10% of SE taxi outs.
I decided to take a look at my own operation during the month of June, and see if it was possible to increase my use of SE taxi out. I was determined to increase my SE taxi out, though honestly, I didn’t think it was possible due to some well held beliefs, or myths. It seems that the A320 pilots hold a paradigm which does not embrace SE taxi. I set out to debunk the no SE taxi myths. Let’s take a look at some of those myths.
I DON’T WANT TO LOAD UP MY FIRST OFFICER WITH A SINGLE ENGINE TAXI; START EM BOTH UP! BUSTED In the past this may have been a reasonable CRM concern. Delta North aircraft would often receive their ‘numbers’ late in the taxi. However with the cutover to the Delta AWABS/WDR we now receive our numbers at the gate. As Captain, you will need to adjust the second engine start to your F/Os comfort level. As the F/O becomes more comfortable with the delayed engine start you can increase the amount of SE taxi time. Almost every F/O that flew with me during June was initially uncomfortable with the delayed engine start. Surprising? No. If only 10% of F/Os were getting landings I’d bet they’d be uncomfortable with landings too. By the end of the trip, SE flow was a standard routine.
IT’S THE FIRST FLIGHT OF THE DAY; START EM BOTH UP. BUSTED During June seven of my flights were first flights of the day (30%). Though the requirement to have 5 minutes of warm-up time limited the amount of SE taxi I was surprised at how many minutes of SE taxi I had actually performed. Even at SMF with a short taxi we recorded 4 minutes of SE taxi.
**Least SE taxi out time for first flights of the day; 3 min, Highest SE taxi out; 6 min, avg SE taxi out 4.6 min**
WE ARE TOO HEAVY FOR SINGLE ENGINE TAXI; START EM BOTH UP BUSTED My weights varied from 128.7 to 165.0 pounds. On all but one flight at max takeoff weight I was able to SE taxi. Some factors for considerations in a successful SE taxi out included concrete vs blacktop. Direction of turn on taxi out (right turns more reasonable N1s than left turns) For example, in the alley at LGA you may need to start both for the initial taxi, then shut one down following the required cool down. Heavy SE taxi requires planning. For example taxi to Rwy 4 at LGA not a problem…crossing Rwy 4 taxi to 13 at taxiway ‘F’ may require an early 2nd engine start.
**Lowest SE taxi out weight;128.7 lbs Highest SE taxi out weight;163.4 lbs. Average SE taxi out weight; 146.1 lbs**
ANY WEIGHTS GREATER THAN MAX LANDING WEIGHT WILL REQUIRE EXCESSIVE N1s; START EM BOTH UP. BUSTED This myth may have developed life during the FNWA Vol 1 days (along with max N1s) See the accompanying spread sheet. The average N1 for breakaway was 32.5%. Again planning ahead will mitigate the impact of breakaway thrust. Have the push crew turn your tail during the push back so that you don’t need to turn into engine 1. If unable to do that, ask for a deeper push than normal to allow forward taxi prior to turning. Carry the thrust into the turn etc. Know where your tail is pointing Is 45% N1 breakaway a big deal if your tail is clear of personnel and carts/equipment? Max N1 breakaway was experienced at LAX (161,300 lbs) at the top of the alley; 48%. Tail was clear of personnel with no objects behind the jet An interesting observation here is that we had a heavier taxi out weight of 163,400 in CVG with only a 37% N1 breakaway. The difference?; Concrete and slight downhill. Plenty of variables affect SE taxi at heavy weights. The key take away is, don’t summarily rule out SE taxi simply based on weight.
**Lowest breakaway 20% N1, highest breakaway 48% N1, Average breakaway 32.5% N1**
I’LL ONLY SAVE A FEW MINUTES, IT’S NOT WORTH THE HASSLE; START EM BOTH UP BUSTED Probably the biggest myth of all. It’s been said before, but it needs to be repeated; the cumulative savings of SE taxi adds up. With the number of flights we operate a day, you and I can make a significant impact in fuel cost savings. What savings did one Captain achieve in June?
**In 20 flights utilizing SE taxi, a total of 143 minutes of SE taxi was recorded.( average SE taxi out was 7.15 minutes!) **
**Total SE taxi fuel saved 2,280 lbs.**
**APU burn during SE taxi: 715 lbs (5 lbs/min)**
**Net SE taxi fuel saved: 1,565 lbs ( 226.8 gallons)**
If you’ve stayed with me so far, thanks. So what‘s the way ahead? First of all, let’s make SE taxi a conscious decision in your flight planning. No different than preflight/taxi/take off/climb out/ cruise/ descent/ approach / landing/ and taxi-in.
I can already hear the howls…………They don’t have park crew waiting for us…They don’t have ext pwr waiting for us….They have us carry too much fuel….Yes, Yes and Yes. However, these are things you as a crew have little control over. Where you have a direct impact on fuel savings however is determining when you start the second engine!
My personal wish list? I’d like to see the cross bleed procedure revisited. Currently the A-320 requires the parking brake set for cross bleed start making that option impractical in most SE taxi scenarios. My data shows that if the APU could have been shut down, and cross bleed utilized for the second engine start an additional 715 pounds of fuel would have been saved.
If you’re still with me great…you may be asking; ‘OK, so what’s in it for me?’ Think job security.
Captains, your next upgrade may be impacted by higher operational costs, but your junior First Officers will be the first to be negatively impacted by higher operational costs. First Officers, become proactive in the single engine start discussion. Captains, I ask you to challenge yourself and increase your SE taxi time
We can do better, we must do better.
**Total SE taxi fuel saved 2,280 lbs.**
**APU burn during SE taxi: 715 lbs (5 lbs/min)**
**Net SE taxi fuel saved: 1,565 lbs ( 226.8 gallons)**
Can you please give an example how you made the forecast for the taxi fuel saved?
Thanks
Yashvin
08-24-2015, 12:15 AM
#110
Gets Weekends Off
Joined APC: Sep 2005
Position: A320 Captain
Posts: 1,114
**In 20 flights utilizing SE taxi, a total of 143 minutes of SE taxi was recorded.( average SE taxi out was 7.15 minutes!) **
**Total SE taxi fuel saved 2,280 lbs.**
**APU burn during SE taxi: 715 lbs (5 lbs/min)**
**Net SE taxi fuel saved: 1,565 lbs ( 226.8 gallons)**
Can you please give an example how you made the forecast for the taxi fuel saved? 5 years old.
Thanks
Yashvin
**Total SE taxi fuel saved 2,280 lbs.**
**APU burn during SE taxi: 715 lbs (5 lbs/min)**
**Net SE taxi fuel saved: 1,565 lbs ( 226.8 gallons)**
Can you please give an example how you made the forecast for the taxi fuel saved? 5 years old.
Thanks
Yashvin
Thread
Thread Starter
Forum
Replies
Last Post
