Date:	Friday 22 May 1953
Time:	04:13
Type:	Curtiss C-46F-1-CU Commando
Owner/operator:	Resort Airlines
Registration:	N1669M
MSN:	22536
Year of manufacture:	1945
Total airframe hrs:	6867 hours
Engine model:	Pratt & Whitney R-2800-75
Fatalities:	Fatalities: 2 / Occupants: 2
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	18 km NE of Des Moines, IA -   United States of America
Phase:	En route
Nature:	Ferry/positioning
Departure airport:	Cheyenne Airport, WY (CYS/KCYS)
Destination airport:	Chicago-O'Hare International Airport, IL (ORD/KORD)
Investigating agency:	CAB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
The aircraft arrived at Cheyenne, Wyoming at 00:38 on a Civil Air Movement flight from New York International Airport. The aircraft departed Cheyenne at 01:32, on an instrument flight plan to Chicago at 7,000 feet. The C-46 progressed uneventfully until it reached Omaha. The pilot contacted Omaha INSAC and requested a change of altitude to 3,000 feet. This was denied because another flight proceeded at 2,600 feet between Des Moines and Omaha. The aircraft flew then into a severe thunderstorm in the vicinity of Des Moines. The aircraft lost control and subsequently the right wing panel failed at the attach angles to the center section due to a strong downward force which exceeded the design strength of the wing. The wing panel then struck the tail, causing it to disintegrate.

PROBABLE CAUSE: "Separation of the right aileron tab motor from its support bracket due to loss of its outboard trunnion while the aircraft was in the severe turbulence of a thunderstorm. These conditions resulted in a tendency to roll erratically, and in conjunction with the extreme turbulence, caused loss of control and subsequent overloading of the wing to the point of failure."

CAB File No. 1-0034
ICAO Accident Digest Circular 39-AN/34 (80-83)

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