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Air carrier pilot reported a potential fuel saving technique to not manually delete the reduced thrust setting during the climb phase of flight.
| Attributes | |
| ACN | 1616525 |
| Time | |
| Date | 201902 |
| Aircraft 1 | |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Climb |
| Flight Plan | IFR |
| Person 1 | |
| Function | Pilot Flying |
| Qualification | Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument |
| Events | |
| Anomaly | Deviation - Procedural Published Material / Policy |
Narrative:
I have developed a technique on very light gross weight short haul (approximately 50 passengers or less) flights to not delete the reduced thrust at 5000 feet AGL; but rather let the FMC take the reduction out by itself; which it accomplishes on its own incrementally by approximately 13;000 feet or so. This adds passenger comfort as the aircraft does not pitch up so severely and is quieter; and I'm wondering if it saves fuel. On very light weight flights there is plenty of excess thrust before the reduction goes away. I know there is a trade off for altitude by keeping the reduction in; but is there any fuel savings by keeping the reduction in on very lightly loaded flights? Is there a trade off by a certain takeoff weight that makes it worth it? If there is a fuel savings; why not make a policy in the fom that says something like 'if aircraft gross weight is at or below ###; ### or ##; ### then do not take reduction out.' I know these light weight flights are the rare exception; not the rule; but on (day)-light travel days; and some originators and terminators; ferry flights; reposition flights and maintenance flights; we experience this and I think it has the potential to provide significant savings if it does indeed save fuel. Thank you for looking into this and I look forward to hearing back if this is viable or not.
Original NASA ASRS Text
Title: Air carrier pilot reported a potential fuel saving technique to not manually delete the reduced thrust setting during the climb phase of flight.
Narrative: I have developed a technique on very light gross weight short haul (approximately 50 Passengers or less) flights to not delete the reduced thrust at 5000 feet AGL; but rather let the FMC take the reduction out by itself; which it accomplishes on its own incrementally by approximately 13;000 feet or so. This adds passenger comfort as the aircraft does not pitch up so severely and is quieter; and I'm wondering if it saves fuel. On very light weight flights there is plenty of excess thrust before the reduction goes away. I know there is a trade off for altitude by keeping the reduction in; but is there any fuel savings by keeping the reduction in on very lightly loaded flights? Is there a trade off by a certain takeoff weight that makes it worth it? If there is a fuel savings; why not make a policy in the FOM that says something like 'If aircraft gross weight is at or below ###; ### or ##; ### then do not take reduction out.' I know these light weight flights are the rare exception; not the rule; but on (day)-light travel days; and some originators and terminators; ferry flights; reposition flights and maintenance flights; we experience this and I think it has the potential to provide significant savings if it does indeed save fuel. Thank you for looking into this and I look forward to hearing back if this is viable or not.
Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.