So how do you avoid 91.605, 121.189, or 135.379?
We don't avoid the regulations:
§ 91.605 Transport category civil airplane weight limitations.
(4) Where the takeoff distance includes a clearway, the clearway distance is not greater than one-half of—
(i) The takeoff run, in the case of airplanes certificated after September 30, 1958, and before August 30, 1959; or
(ii) The runway length, in the case of airplanes certificated after August 29, 1959.
(c) No person may take off a turbine-engine-powered transport category airplane certificated after August 29, 1959, unless, in addition to the requirements of paragraph (b) of this section—
(1) The accelerate-stop distance is no greater than the length of the runway plus the length of the stopway (if present); and
(2) The takeoff distance is no greater than the length of the runway plus the length of the clearway (if present); and
(3) The takeoff run is no greater than the length of the runway.d in the Airplane Flight Manual for the elevation of the airport and for the ambient temperature existing at the time of takeoff;
§ 121.189 Airplanes: Turbine engine powered: Takeoff limitations.
(1) The accelerate-stop distance must not exceed the length of the runway plus the length of any stopway.
(2) The takeoff distance must not exceed the length of the runway plus the length of any clearway except that the length of any clearway included must not be greater than one-half the length of the runway.
(3) The takeoff run must not be greater than the length of the runway.
§ 135.379 Large transport category airplanes: Turbine engine powered: Takeoff limitations.
(1) The accelerate-stop distance, as defined in §25.109 of this chapter, must not exceed the length of the runway plus the length of any stopway.
(2) The takeoff distance must not exceed the length of the runway plus the length of any clearway except that the length of any clearway included must not be greater than one-half the length of the runway.
(3) The takeoff run must not be greater than the length of the runway
However please show me where it says we MUST use the CLEARWAY? As you have mentioned TWA, please tell me how you accounted for CLEARWAYS in the DC9? The MD90 doesn't have CLEARWAYS in the AFM, nor does the MD11.
I would be on a fool's errand if I did not increase thrust on the remaining engine (s) rather than hope to clear that ridgeline 7 miles away by 35 feet.
I think that you have to look at NET and GROSS gradients.
TWA also did not assess more than 300 feet each side of the takeoff flight path (beyond the airport boundary), which was another reason for advancing to takeoff power in the event of an engine failure.
We analyze 900 meters either side!
Are you talking about a particular aircraft type?
Mutt