Aviation Accident Report: TWA Flight 6/Conclusion

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Aviation Accident Report: TWA Flight 6
H. Branch, O. Ryan, G. G. Mason, Jr., and G. P. Baker for the Civil Aeronautics Board

Conclusion

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2171435Aviation Accident Report: TWA Flight 6 — ConclusionH. Branch, O. Ryan, G. G. Mason, Jr., and G. P. Baker for the Civil Aeronautics Board

III.

CONCLUSION

Findings

We find, upon all of the evidence available to Board at this time, that the facts relating to the accident involving NC 17315, which occurred near Robertson, Missouri, on January 23, 1941, are as follows:

The accident which occurred at approximately 4:14 A.M., January 23, 1941, to TWA's Trip 6 of that date, resulted in major damage to aircraft NC 17315, fatal injuries to one passenger and one member of the crew, serious injuries to four passengers and one member of the crew, and minor injuries to six passengers and one member of the crew.

At the time of the accident, TWA held a currently effective certificate of public convenience and necessity and an air carrier operating certificate authorizing it to conduct the flight.
Captain Scott and First Officer DioGuardi were physically qualified and held proper certificates of competency to operate as air carrier pilots over the route between Kansas City and St. Louis, Missouri.
Aircraft NC 17315 was currently certificated as airworthy at the time of the accident.
Trip 6 was cleared in accordance with proper procedure from Kansas City, Missouri to St. Louis, Missouri.
At the time of departure from Kansas City and at the time of the accident, the gross weight of the airplane did not exceed the permissible gross weight^[1] and its load was properly distributed with reference to the location of the center of gravity.
At the time of departure from Kansas City to St. Louis the airplane carried sufficient fuel to permit flight at normal cruising power to St. Louis and thereafter for about five hours, thus making available to Captain Scott a choice between a number of alternate airports.

Trip 6 proceeded normally from Kansas City until it arrived over the St. Louis radio range station at 4:04 A. M. at an altitude of 1,700 feet.
Successive weather reports had indicated a constantly and rapidly lowering ceiling and a constantly diminishing visibility at the Lambart-St. Louis Airport.
After arriving over the St. Louis radio range station, Captain Scott begin a standard instrument let-down-through procedure.
While executing this procedure and about two minutes before he broke out of the overcast, Captain Scott received the 4:09 A. M. weather report, which indicated a variable ceiling of 400 feet with lower scattered clouds at 200 feet and visibility of two miles with light drizzle and light fog.
Although the minimum ceiling prescribed for TWA at St. Louis by the Civil Aeronautics Administration was 400 feet, Captain Scott, instead of going to his alternate when he observed that the ceiling was below that minimum continued his descent and broke out of the overcast at approximately 300 feet.
Captain Scott broke out of the overcast too close to runway No. 1 to effect a normal landing from that altitude.
After breaking out of the overcast, Captain Scott continued across the airport at an altitude of 200 feet or less.
At no time during the flight across the airport of beyond the airport did Captain Scott make use of the landing lights on the airplane.

Shortly after passing over the west boundary of the airport, the pilot started a left turn; while in the turn the airplane contacted trees 113 feet above the level of the airport and 2,200 feet southwest of the southwest and of runway No. 4.
Full power was applied to the engines in an attempt to pull up but other trees were struck and the pilot lost control. The aircraft crashed to the ground at a point approximately one-fourth of a mile southwest of the airport boundary.
Captain Scott was flying the airplane during the entire flight from Kansas City to St. Louis and was at the controls at the time the airplane first contacted the trees.
Aircraft NC 17135 and all of its equipment functioned normally up until the time the accident occurred.

Probable Cause

Upon the basis of tho foregoing findings and the entire record available to us at this time, we find that the probable cause of the accident to NC 17315 (TWA Trip 6) on January 23, 1941, was the action of the pilot in attempting a landing under adverse weather conditions in disregard of the minimums prescribed by the Civil Aeronautics Administration and in maneuvering for such landing at a dangerously low altitude.

Recommendations

The Board recommends that the Administrator of Civil Aeronautics encourage the development and installation of a continuously monitoring apparatus for ceiling light projectors at all airports used by air carriers.
The purpose of this device is to give a continuous observation of the height of clouds and through proper setting of the instrument a change in the ceiling to some predetermined lower value would automatically set off an alarm. When such device is in operation, scud clouds moving across the field would be detected in this manner.
The Board has recommended to the Administrator that when a solid cloud cover prevails at an altitude of 800 feet or less and the horizontal visibility is officially reported to be less than five miles, the height of the ceiling shall be from the base of the lowest cloud form officially reported. The Board suggested that this recommendation be made effective and enforced until such time as additional studies indicated that other action of a more fundamental and permanent character should be taken. It is understood that such action was taken by the Administrator immediately to carry the recommendation into effect.

BY THE BOARD:

/S/ Harllee Branch

Harlee Branch, Chairman

/S/ Oswald Ryan

Oswald Ryan

/S/ G. Grant Mason, Jr.

G. Grant Mason, Jr.

/S/ George P. Baker

George P. Baker

Edward F. Warner, Vice Chairman, did not
take part in the adoption of this report
and recommendation.

↑ The "Standard gross weight" of an airplane is the maximum allowable gross weight for landing, while the "provisional gross weight" for an airplane is the maximum allowable gross weight for take-off. when an airplane takes off at its maximum provisional gross weight, the weight of the airplane is reduced by gasoline consumption at least to the standard gross weight for landing prior to arrival at its next scheduled stop. If sufficient gasoline has not been consumed between the time of take off and an emergency landing, gasoline can be dumped by the use of tested and approved dump valves in order to reduce the total weight to the approved gross weight for lending. At the time of the accident, the total weight of the airplane had been reduced, since its departure from Kansas City, by approximately 900 pounds.

[1] The "Standard gross weight" of an airplane is the maximum allowable gross weight for landing, while the "provisional gross weight" for an airplane is the maximum allowable gross weight for take-off. when an airplane takes off at its maximum provisional gross weight, the weight of the airplane is reduced by gasoline consumption at least to the standard gross weight for landing prior to arrival at its next scheduled stop. If sufficient gasoline has not been consumed between the time of take off and an emergency landing, gasoline can be dumped by the use of tested and approved dump valves in order to reduce the total weight to the approved gross weight for lending. At the time of the accident, the total weight of the airplane had been reduced, since its departure from Kansas City, by approximately 900 pounds.

[1]