I saw a lot of posts recently talking about fuel effiency, and I thought it’d be a good idea to create a comprehensive detailed post about single engine taxi operation.
I rarely, rarely see single-engine operations in IF!
In real life, we do use single engine taxi a lot, because it is very very efficient and on all flights we can save tons of fuel, which translates to tons of money, especially when there’s delay on the ground (departure line-up, deicing, etc…). For the non-believers, I added below stats and data I got from IF to prove that single-engine taxi is worth it. I also added aircraft-specific procedures for those who aim for that realism.
If you happen to find erroneous data or procedures in my thread, please let me know and I will update.
General Tips: (Most also apply for normal taxi)
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Try not to exceed 40% N1, and NEVER exceed 50% N1 while taxiing.
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Try to keep the engine that’s convenient for upcoming taxi route. (Ex. Keep #1 engine if sharp right turn expected)
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If you have to make a turn on the same side of your turning engine, get some speed before turning so you don’t get stuck.
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All engines should be on at least 2 minutes before take-off for temperature and wear.
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Try not to exceed 10kts in a turn, and NEVER exceed 15kts in a turn.
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Keep your nose wheel straight to accelerate and then turn when you have momentum.
- On tri or quad jets, we keep 2 engines on.
When to avoid single-engine operations
- When taxiways are contaminated or slippery
- When short taxi route is expected
The savings
Naturally, at idle, you will burn 50% less fuel, but while taxiing, you will need additional thrust on the engine that’s running to compensate the lack of power of the other engine. Below, you can see the data I pulled from IF.
All tests were made under the same conditions
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Maximum Takeoff Weight (MTOW)
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15 degrees Celsius
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No wind
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Same airport and runway
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Maintaining a speed of 15 knots in a straight line
Most efficient aircrafts: A330 - A380 - B717 - B744 - B748 - B763
Least efficient aircrafts: B757 - DC10 - MD11
Aircraft specific data and procedures
I’ve excluded military aircrafts since they don’t really care about burning ‘em gallons.
I’m also an Airbus pilot, so I do not know procedures for most Boeings.
Airbus A318
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Dual Engine @ 720 kgph
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Single Engine @ 630 kgph
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Potential savings of 12.5%, up to 50% if idle for long periods of time.
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Realistic procedure: A318 is hydraulically limited to only single-engine on #1. (NWS and Brakes)
Airbus A319
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Dual Engine @ 775 kgph
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Single Engine @ 675 kgph
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Potential savings of 12.9%, up to 50% if idle for long periods of time.
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Realistic procedure: A319 is hydraulically limited to only single-engine on #1. (NWS and Brakes)
Airbus A320
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Dual Engine @ 660 kgph
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Single Engine @ 600 kgph
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Potential savings of 10%, up to 50% if idle for long periods of time.
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Realistic procedure: A320 is hydraulically limited to only single-engine on #1. (NWS and Brakes)
Airbus A321
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Dual Engine @ 725 kgph
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Single Engine @ 610 kgph
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Potential savings of 15.8%, up to 50% if idle for long periods of time.
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Realistic procedure: A321 is hydraulically limited to only single-engine on #1. (NWS and Brakes)
Airbus A330-200F
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Dual Engine @ 1374 kgph
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Single Engine @ 687 kgph @ IDLE
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Potential savings of 50%
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Realistic procedure: You can single-engine on any engine. Do not exceed 40% N1.
Airbus A330-300
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Dual Engine @ 1388 kgph
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Single Engine @ 694 kgph @ IDLE
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Potential savings of 50%
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Realistic procedure: You can single-engine on any engine. Do not exceed 40% N1.
Airbus A340-600
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Quad Engine @ 2480 kgph
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Dual Engine @ 1563 kgph @ 34% N1
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Potential savings of 37%, up to 50% if idle for long periods of time.
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Realistic procedure: Keep 2 opposite engines on, inners or outers. High thrust may be required to get rolling, but do not exceed 50%.
Airbus A380
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Quad Engine @ 3076 kgph
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Dual Engine @ 1538 kgph @ IDLE
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Potential savings of 50%
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Realistic procedure: Keep 2 opposite engines on, inners or outers.
Boeing 717
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Dual Engine @ 718 kgph
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Single Engine @ 359 kgph @ IDLE
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Potential savings of 50%
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Realistic procedure: Unknown
Boeing 737-700
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Dual Engine @ 823 kgph
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Single Engine @ 596 kgph @ 31% N1
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Potential savings of 27.6%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown
Boeing 737 BBJ
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Dual Engine @ 904 kgph
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Single Engine @ 611 kgph @ 32% N1
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Potential savings of 32.4%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown
Boeing 737-800
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Dual Engine @ 849 kgph
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Single Engine @ 611 kgph @ 32% N1
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Potential savings of 28%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown
Boeing 737-900
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Dual Engine @ 915 kgph
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Single Engine @ 611 kgph @ 32% N1
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Potential savings of 33.2%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown
Boeing 747-400 & 747-8
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Quad Engine @ 2404 kgph
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Dual Engine @ 1202 kgph @ IDLE
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Potential savings of 50%
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Realistic procedure: Keep 2 opposite engines on, inners or outers.
Boeing 757-200 **NOT RECOMMENDED**
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Dual Engine @ 2965 kgph
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Single Engine @ 2361 kgph @ 63% N1
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Potential savings of 20.4%, up to 50% if idle for long periods of time.
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Realistic procedure: Do not single-engine this aircraft (High thrust hazard)
Boeing 767-300
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Dual Engine @ 1231 kgph
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Single Engine @ 616 kgph @ IDLE
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Potential savings of 50%
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Realistic procedure: You can use any engine.
Boeing 777-200ER
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Dual Engine @ 1879 kgph
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Single Engine @ 1226 kgph @ 26% N1
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Potential savings of 34.8%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Boeing 777-200F
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Dual Engine @ 2407 kgph
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Single Engine @ 1543 kgph @ 26% N1
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Potential savings of 35.8%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Boeing 777-200LR
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Dual Engine @ 2349 kgph
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Single Engine @ 1493 kgph @ 25% N1
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Potential savings of 36.4%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Boeing 777-300ER
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Dual Engine @ 2180 kgph
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Single Engine @ 1422 kgph @ 26% N1
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Potential savings of 34.8%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Boeing 787-8
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Dual Engine @ 1263 kgph
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Single Engine @ 845 kgph @ 26% N1
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Potential savings of 33%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Boeing 787-9
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Dual Engine @ 1398 kgph
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Single Engine @ 938 kgph @ 28% N1
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Potential savings of 32.9%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Boeing 787-10
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Dual Engine @ 1366 kgph
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Single Engine @ 938 kgph @ 28% N1
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Potential savings of 31.3%, up to 50% if idle for long periods of time.
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Realistic procedure: You can use any engine.
Cessna 172
Really ? What are you thinking ? ;)
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Potential savings of 100% if you turn one engine off.
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Realistic procedure: You can push the aircraft and the only thing you’re burning are calories.
Bombardier CRJ-200
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Dual Engine @ 274 kgph
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Single Engine @ 152 kgph @ 27% N1
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Potential savings of 44.5%, up to 50% if idle for long periods of time.
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Realistic procedure: CRJ is limited and can only single-engine on #2.
Bombardier CRJ-700
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Dual Engine @ 318 kgph
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Single Engine @ 190 kgph @ 27% N1
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Potential savings of 40.3%, up to 50% if idle for long periods of time.
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Realistic procedure: CRJ is limited and can only single-engine on #2.
Bombardier CRJ-900
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Dual Engine @ 324 kgph
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Single Engine @ 190 kgph @ 27% N1
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Potential savings of 41.4%, up to 50% if idle for long periods of time.
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Realistic procedure: CRJ is limited and can only single-engine on #2.
Bombardier CRJ-1000
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Dual Engine @ 333 kgph
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Single Engine @ 197 kgph @ 28% N1
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Potential savings of 40.8%, up to 50% if idle for long periods of time.
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Realistic procedure: CRJ is limited and can only single-engine on #2.
Bombardier Dash-8 Q400
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Dual Engine @ 269 kgph
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Single Engine @ 167 kgph
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Potential savings of 37.9%, up to 50% if idle for long periods of time.
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Realistic procedure: Dash-8 electrical system limits that only the #2 engine must be used for single-engine operations.
Embraer 170 & 175
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Dual Engine @ 651 kgph
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Single Engine @ 442 kgph @ 33% N1
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Potential savings of 32.1%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown.
Embraer 190
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Dual Engine @ 683 kgph
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Single Engine @ 440 kgph @ 33% N1
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Potential savings of 35.6%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown.
Embraer 195
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Dual Engine @ 694 kgph
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Single Engine @ 440 kgph @ 33% N1
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Potential savings of 36.6%, up to 50% if idle for long periods of time.
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Realistic procedure: Unknown.
DC-10 **NOT RECOMMENDED**
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3 Engine @ 3634 kgph
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Dual Engine @ 2849 kgph @ 43% N1
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Potential savings of 21.6%, up to 33% if idle for long periods of time.
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Realistic procedure: Use #1 and #3. Not recommended (High thrust hazard)
DC-10F **NOT RECOMMENDED**
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3 Engine @ 3669 kgph
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Dual Engine @ 2924 kgph @ 44% N1
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Potential savings of 20.3%, up to 33% if idle for long periods of time.
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Realistic procedure: Use #1 and #3. Not recommended (High thrust hazard)
MD-11 **NOT RECOMMENDED**
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3 Engine @ 4830 kgph
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Dual Engine @ 3957 kgph @ 43% N1
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Potential savings of 18.1%, up to 33% if idle for long periods of time.
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Realistic procedure: Use #1 and #3. Not recommended (High thrust hazard)
MD-11F **NOT RECOMMENDED**
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3 Engine @ 4653 kgph
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Dual Engine @ 3782 kgph @ 42% N1
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Potential savings of 18.7%, up to 33% if idle for long periods of time.
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Realistic procedure: Use #1 and #3. Not recommended (High thrust hazard)
- I will definitely use single-engine procedures now for extra realism and fuel efficiency.
- I don’t really care about burning extra fuel, I want all my engines.
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