Date:	Saturday 14 February 1953
Time:	17:10
Type:	Douglas DC-6
Owner/operator:	National Airlines
Registration:	N90893
MSN:	43057/73
Year of manufacture:	1947
Total airframe hrs:	15994 hours
Engine model:	Pratt & Whitney R-2800-CB16
Fatalities:	Fatalities: 46 / Occupants: 46
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	32 km SE off Mobile Point, AL, USA [Gulf of Mexico] -   Atlantic Ocean
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Tampa International Airport, FL (TPA/KTPA)
Destination airport:	New Orleans-Moisant Field, LA (MSY/KMSY)
Investigating agency:	CAB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Flight 470 originated at Miami, for New Orleans, with one stop scheduled at Tampa. From Miami the VFR flight was uneventful, with departure at 14:15, with the Tampa landing at 15:15. The flight took off from Tampa at 15:43 for an IFR flight across the Gulf of Mexico to New Orleans. Cruising altitude was FL145. At 16:49, Flight 470 reported passing over NA-2 check point at 16:45 at 14,500 feet, and estimated being over NA-1 at 17:10. It also reported, "Thunderstorms all quadrants..." Pensacola radio received and acknowledged this message, and advised the flight of "severe turbulence" between NA-1 and New Orleans as reported by a DC-6 crew that had landed ahead of Flight 470. At 16:54, the flight advised Pensacola that it was reducing power because of turbulence and five minutes later requested Air Route Traffic Control clearance to descend from 14,500 feet to 4,500 feet. This was granted within a minute or so. At 17:03, the Flight advised Pensacola of passing through 10,000 feet, and at 17:12, advised that it had reached 4,500 feet at 17:10. Pensacola repeated this message back to the flight and gave it the 16:48 New Orleans special weather: measured 800 feet overcast, visibility 10 miles, wind north-northeast 25 mph, with gusts to 34, the altimeter 29.61; barometer unsteady. The flight acknowledged and there were no further radio contacts. The aircraft had apparently crashed in the Gulf of Mexico. Some wreckage and bodies were found the next day, but the majority of the wreckage was found on May 20.

PROBABLE CAUSE: "The loss of control followed by the in-flight failure and separation of portions of the airframe structure while the aircraft was traversing an intense frontal-wave type storm of extremely severe turbulence, the severity and location of which the pilot had not been fully informed."

CAB File No. 1-0013
ICAO Accident Digest Circular 39-AN/34 (36-49)

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