Hotel Sierra Bravo
Well-Known Member
My plain English interpretation of 121.91 (a) is: operate a turbine engine airplane at a weight that if one engine is inoperative it is able to be operated with 2000 foot vertically within 5 sm of intended track above all terrain and obstacles. The descent should encompass a positive slope at 1500 feet above the airport and the aircraft should be able to land within 60 percent of the effective length of the runway for turbojet powered airplanes, from a point 50 feet above the intersection of the obstruction clearance plane (121.97).
Is this a correct interpretation as it applies to modern operations? How would you phrase this regulation into plain English?
I realize the regs were written to encompass several situations, but does anyone know the significance aircraft certificated before 1958 and 1959?
Thanks!!
HSB
121.191 Airplanes: Turbine engine powered: En route limitations: One engine inoperative.
(a) No person operating a turbine engine powered airplane may take off that airplane at a weight, allowing for normal consumption of fuel and oil, that is greater than that which (under the approved, one engine inoperative, en route net flight path data in the Airplane Flight Manual for that airplane) will allow compliance with paragraph (a) (1) or (2) of this section, based on the ambient temperatures expected en route:
(1) There is a positive slope at an altitude of at least 1,000 feet above all terrain and obstructions within five statute miles on each side of the intended track, and, in addition, if that airplane was certificated after August 29, 1959 (SR 422B) there is a positive slope at 1,500 feet above the airport where the airplane is assumed to land after an engine fails.
(2) The net flight path allows the airplane to continue flight from the cruising altitude to an airport where a landing can be made under §121.197, clearing all terrain and obstructions within five statute miles of the intended track by at least 2,000 feet vertically and with a positive slope at 1,000 feet above the airport where the airplane lands after an engine fails, or, if that airplane was certificated after September 30, 1958 (SR 422A, 422B), with a positive slope at 1,500 feet above the airport where the airplane lands after an engine fails
Is this a correct interpretation as it applies to modern operations? How would you phrase this regulation into plain English?
I realize the regs were written to encompass several situations, but does anyone know the significance aircraft certificated before 1958 and 1959?
Thanks!!
HSB
121.191 Airplanes: Turbine engine powered: En route limitations: One engine inoperative.
(a) No person operating a turbine engine powered airplane may take off that airplane at a weight, allowing for normal consumption of fuel and oil, that is greater than that which (under the approved, one engine inoperative, en route net flight path data in the Airplane Flight Manual for that airplane) will allow compliance with paragraph (a) (1) or (2) of this section, based on the ambient temperatures expected en route:
(1) There is a positive slope at an altitude of at least 1,000 feet above all terrain and obstructions within five statute miles on each side of the intended track, and, in addition, if that airplane was certificated after August 29, 1959 (SR 422B) there is a positive slope at 1,500 feet above the airport where the airplane is assumed to land after an engine fails.
(2) The net flight path allows the airplane to continue flight from the cruising altitude to an airport where a landing can be made under §121.197, clearing all terrain and obstructions within five statute miles of the intended track by at least 2,000 feet vertically and with a positive slope at 1,000 feet above the airport where the airplane lands after an engine fails, or, if that airplane was certificated after September 30, 1958 (SR 422A, 422B), with a positive slope at 1,500 feet above the airport where the airplane lands after an engine fails
