37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 1486053 |
Time | |
Date | 201709 |
Aircraft 1 | |
Make Model Name | Widebody Transport |
Operating Under FAR Part | Part 121 |
Flight Phase | Parked |
Flight Plan | IFR |
Person 1 | |
Function | Captain |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Experience | Flight Crew Total 16296 Flight Crew Type 8664 |
Events | |
Anomaly | Deviation - Procedural Published Material / Policy Deviation - Procedural FAR |
Narrative:
The purpose of this report is to illustrate possible conflicts not only within the fom (flight operations manual) but also with the fom and flight manuals (in this case with the 787 FM) vs far 121.11.ref: fom far applicability. 'Far 121.11 states that pilots operating in a foreign country must comply with the air traffic rules and local airport rules of that country; except when part 121 fars are more restrictive and may be followed without violating the rules of that country.'ref: fom below 10;000 feet international. 'In the interest of fuel economy; pilots are encouraged to request waiver of published speed restrictions after considering factors as…'this fom paragraph seems to be in conflict with far 121.11. Example: departing hkg climbing through 3;000 feet the controller advises 'no speed restrictions'. Following far 121.11 the pilots would; after flap retraction climb at 250 knots or the clean maneuvering speed if greater (far 91.117 d) until 10;000 feet; then accelerate to cruise climb speed. Following fom; the pilots could accelerate to cruise climb speed after flap retraction. This high speed; low climb rate from 3;001 to 10;000 feet places the aircraft in a much higher threat for factors such as cockpit noise (communications); terrain (closure rate); uncontrolled traffic (drones); turbulence (flight attendant injuries); and bird strikes (catastrophic). Therefore the possible fuel savings seems minor compared to possible threats imposed preforming this nonstandard maneuver. Ref: 787 FM'on some international flights; speeds above 250 knots below 10;000 feet MSL are authorized. The FMC climb page can be edited to delete the 250 knot restriction.' this statement seems inconsistent with far 121.11; far 91.117; and fom style of flying 'all maneuvers not necessary to the safe and orderly progress of the flight are to be avoided.' the flight manual statement is possibly only to illustrate how one can modify or manipulate the FMC but it implies that climbing at a high speed below 10;000 feet is acceptable. Question: is flying at 340 knots at 3;001 consistent with the 'safe and orderly progress of the flight?' ref: fom operating priorities 'the order of operating priorities is: safe; comfortable; on time; efficient.'question: is operating at a speed of 340 knots at 3001 feet more safe or less safe than at the standard of 250 knots/ clean maneuvering speed (far 91.117d). The possible 'fuel savings' would fall under priority number 4; 'efficient'. Conclusions:turbojet and turbofan engines both are more fuel efficient with increased speed however the turbojets of the past needed much more speed compared to modern turbofans in order for the efficiencies to increase. Thus; 30 years ago high speed climb outs resulted in fuel savings not realized by a normal climb profile. Because modern turbofans can enjoy these fuel savings at lower speeds (250 knots/clean maneuvering speed) the fuel savings at higher speeds are not as significant. Is it possible that fom is a statement that has been around since the days of turbojet's in [company's] fleet and has not been evaluated since? Therefore; are the 'fuel savings' of a turbofan powered aircraft in our current inventory preforming a high speed low altitude climb from 801 /3001 feet to 10;000 feet) vs a normal climb profile 801/3001 feet 250 knots/clean maneuvering speed to 10;000 feet) significant enough to justify the increased risks as previously mentioned?
Original NASA ASRS Text
Title: Air carrier Captain reported the debate between safety and efficiency during international departures where speeds in the climb below 10000 feet are unrestricted.
Narrative: The purpose of this report is to illustrate possible conflicts not only within the FOM (Flight Operations Manual) but also with the FOM and flight manuals (in this case with the 787 FM) vs FAR 121.11.Ref: FOM FAR Applicability. 'FAR 121.11 states that pilots operating in a foreign country must comply with the air traffic rules and local airport rules of that country; except when Part 121 FARs are more restrictive and may be followed without violating the rules of that country.'Ref: FOM Below 10;000 feet International. 'In the interest of fuel economy; pilots are encouraged to request waiver of published speed restrictions after considering factors as…'This FOM paragraph seems to be in conflict with FAR 121.11. Example: Departing HKG climbing through 3;000 feet the controller advises 'no speed restrictions'. Following FAR 121.11 the Pilots would; after flap retraction climb at 250 knots or the clean maneuvering speed if greater (FAR 91.117 d) until 10;000 feet; then accelerate to cruise climb speed. Following FOM; the pilots could accelerate to cruise climb speed after flap retraction. This high speed; low climb rate from 3;001 to 10;000 feet places the aircraft in a much higher threat for factors such as cockpit noise (communications); terrain (closure rate); uncontrolled traffic (drones); turbulence (Flight Attendant injuries); and bird strikes (catastrophic). Therefore the possible fuel savings seems minor compared to possible threats imposed preforming this nonstandard maneuver. Ref: 787 FM'On some international flights; speeds above 250 knots below 10;000 feet MSL are authorized. The FMC CLB page can be edited to delete the 250 knot restriction.' This statement seems inconsistent with FAR 121.11; FAR 91.117; and FOM Style of Flying 'All maneuvers not necessary to the safe and orderly progress of the flight are to be avoided.' The Flight Manual statement is possibly only to illustrate how one can modify or manipulate the FMC but it implies that climbing at a high speed below 10;000 feet is acceptable. Question: is flying at 340 knots at 3;001 consistent with the 'safe and orderly progress of the flight?' Ref: FOM Operating Priorities 'The order of Operating Priorities is: Safe; Comfortable; On Time; Efficient.'Question: Is operating at a speed of 340 knots at 3001 feet more safe or less safe than at the standard of 250 Knots/ Clean maneuvering speed (FAR 91.117d). The possible 'fuel savings' would fall under priority number 4; 'Efficient'. Conclusions:Turbojet and Turbofan engines both are more fuel efficient with increased speed however the turbojets of the past needed much more speed compared to modern Turbofans in order for the efficiencies to increase. Thus; 30 years ago high speed climb outs resulted in fuel savings not realized by a normal climb profile. Because modern Turbofans can enjoy these fuel savings at lower speeds (250 knots/clean maneuvering speed) the fuel savings at higher speeds are not as significant. Is it possible that FOM is a statement that has been around since the days of turbojet's in [Company's] fleet and has not been evaluated since? Therefore; are the 'fuel savings' of a Turbofan powered aircraft in our current inventory preforming a high speed low altitude climb From 801 /3001 feet to 10;000 feet) vs a normal climb profile 801/3001 feet 250 knots/clean maneuvering speed to 10;000 feet) significant enough to justify the increased risks as previously mentioned?
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.