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FLIGHT

SECTION 3603 - DC-3 AIRPORT ANALYSES (CONT'D.)

Headwind component is defined as that Vectorial portion of the headwind which is directly in line with the direction of the runway. For example, an airplane taking off in runway 4 at La Guardia Field with a 25 mph wind from 80° has a headwind component of 19 mph. A set of curves from which the pilot can make this calculation is included with the attached data. This data lists the maximum allowable take-off and landing weight for 20 airports into which Colonial is permitted to operate (regulars, alternate and provisionals), that are restricted. All other airports for which the company is authorized have no weight restrictions for landing and take-off. Certain runways have been declared "not authorized" and restrictions have been removed from several others. For example, take-off at Rutland to the SE and landing to the NW is "not authorized". The 25 mph restrictions for landing to the SE no longer exists.

Effective November 18, 1947, pilots will exercise their own discretion as regards cross wing component in the matter of landings and take-offs. This procedure will simplify certain obvious operating and dispatching problems which arise from establishing a fixed maximum allowable cross wind component. Data as to the maximum recommended cross wind component for safe operation is very meager. The following is quoted from the CAA Flight Engineering Report #14 dated October 31, 1944:

"To the best of our knowledge, such a critical cross wind component has never been established for the airplane considered in this report. It has been variously estimated from 10 to 20 miles an hour and is assumed in this report to be 15 miles per hour."

This information will eventually be incorporated in a revised DC-3 airplane manual.

This supersedes the information concerning cross wind component contained in the original explanation sheet which accompanied Revision #103 dated November 4, 1947, to the Operating Manual.

With the establishing of these take-off weights based on the performance of the airplane, the pilot retains the right to refuse full gross weight in the special cases where he feels that heavy icing, extreme turbulence or excessive outside air temperature considerably reduce the airplane's performance. In this connection, pilots are reminded that up to rated power (900 HP - G102, 1050 HP - R1830) can be used in cases where a rapid ascent is desired thru icing.

Nothing contained in these data should be construed by the pilots as an infringement upon his powers of discretion in regard to safe operation. It will be noted that in many cases, the maximum take-off weight permitted on a runway will not be less than was previously allowed.

11/17/47  (11/4/47)                     FLIGHT