Compiled by Wayne Blanchard Sep 10, 2023 for upload to: http://www.usdeadlyevents.com/

–53 Aviation Safety Network Database. “Accident Description…Strato-Freight, 07 Jun 1949.”

–53 Baugher. 1942 USAAF Serial Numbers (42-91974 to 42-110188). 10-28-2011 rev.

–53 Civil Aeronautics Board AIR. Strato-Freight, Inc., San Juan, Puerto Rico, June 7, 1949. 2-10-1950.

–53 Eckert. “Fatal commercial air transport crashes, 1924-1981.” AJFM&P, 3/1, Mar 1982, p.53.

–53 Planecrashinfo.com. “1949…Strato Freight…San Juan-Miami…June 7, 1949.

Narrative Information

Aviation Safety Network, Flight Safety Foundation, Database, 1949:

“Curtiss C-46 NC92857 had been flown from Newark to San Juan, June 4, 1949. During the time that the aircraft was on the ground at San Juan, the flap follow-up cable was replaced, and both engines were checked. Since the right engine misfired during the check, 13 new spark plugs were installed. Shortly before midnight, June 6, 75 passengers, including five infants in arms and 14 children between the ages of two and 12, boarded the aircraft. Since there were only 65 seats in the cabin which necessitated seating some of the passengers double in one seat. Although the Weight and balance manifest for the flight indicated a total weight of 44,500 pounds, the aircraft actually weighed 48,709 pounds, which was 3,709 pounds in excess of the 45,000 pounds certificated aircraft weight.

“At approximately 00:10 the aircraft taxied to runway 27 where the pre-takeoff check was accomplished at which time engines and flight controls operated normally. Takeoff was accomplished at 00:21 after the San Juan Tower had transmitted an instrument clearance to the flight authorizing it to cruise at 8,500 feet to Miami. One minute after the aircraft left the ground and at an indicated air speed of approximately 115 miles per hour and at an indicated altitude of 250 feet, the right engine began to backfire severely and lose power. No attempt was made to feather the propeller of the right engine. An emergency was declared, and the tower cleared the flight to land on runway 09. But, since airspeed was low and altitude could not be maintained, the aircraft was flown straight ahead for a crash landing 200 yards off the shore at Punta Salinas. During a six minute period that the aircraft remained afloat the crew pushed two uninflated life rafts into the water and furnished several passengers with life preservers. Considerable confusion existed during the ditching operation since none of the passengers had received any instruction in the location or use of emergency equipment. Of the 81 occupants, only 23 passengers and five crew members survived.

PROBABLE CAUSE: “The Board determines that the probable cause of this accident was the loss of power of the right engine before the aircraft attained the optimum single engine climb speed which, together with the overloaded condition of the aircraft, resulted in it losing altitude and settling into the sea.”

“Follow-up / safety actions: The CAB revoked the license of Strato-Freight Inc. July 1949.

“Sources: CAB File No. 1-0069.” (Aviation Safety Network Database. “Accident Description…Strato-Freight, 07 Jun 1949.”)

Baugher: “Curtiss C-46A-50-CU Commando….101051 (c/n 30506) to RFC at Walnut Ridge Oct 26, 1945. To Strato-Freight, Inc of Puerto Rico as NC92857. Crashed into sea 10 km W of San Juan Jun 7, 1949 after departing San Juan on flight to Miami. 6 crew, 75 passengers on board, of which 52 passengers and one crew member were killed. Probable cause of accident was loss of power of right engine which caused the aircraft to lose altitude and settle into the sea because of overloaded condition of the aircraft. The wrong sparkplugs had been installed during maintenance. CAB revoked the license of Strato-Freight in July of 1949.” (Baugher. 1942 USAAF Serial Numbers (42-91974 to 42-110188). 10-28-2011 rev.)

Civil Aeronautics Board. Accident Investigation Report:

“The Accident

“At 0025, June 7, 1945, a C-46A aircraft, NC-92857, owned and operated by Strato-Freight, Inc., a large irregular carrier, crash landed in the Atlantic Ocean, 6.4 statute miles west of Isla Grande Airport, San Juan, Puerto Rico. Of the 75 passengers and crew of six on board, 52 passengers and one crew member lost their lives. The aircraft sank.

“History of the Flight

“The aircraft had been flown from Newark, N.J., to San Juan, June 4, 1949, with a crew consisting of Captain Lee Howard Wakefield, and Copilots John Connell and George Cary, and Stewardess Judith Hale. No difficulties were experience in the operation of the aircraft except that during the approach for the landing at San Juan, the flaps extended to the full down position when the cockpit control was placed in the ¼ down position. Captain Wakefield had been previously advised at Newark that the follow-up cable, which controls the extension of the flaps, was frayed.

“During the time that the aircraft was on the ground at San Juan, the flap follow-up cable was replaced, and both engines were checked. Since the right engine misfired during the check, 13 new AX-LS-87 spark plugs were installed. After the completion of this work the aircraft was declared to be airworthy for the return trop to Newark by a certificated mechanic employed by the aircraft repair agency in San Juan which accomplished turnaround maintenance for Strato-Freight, Inc.

“Shortly before midnight, June 6, seventy-five passengers, including five infants in arms and 14 children between the ages of two and 12, boarded the aircraft. There was also placed on board 1,116 pounds of baggage, and according to the Weight and Balance Manifest there was 7,125 pounds of fuel and oil on board. With the addition of a third pilot, Alfred Cockrill, and a Steward, Ismael Gonzalez, the crew for the northbound flight was the same as that of the flight of June 4 and 5 to San Juan.

“According to the crew, all occupants in the cabin were seated at the time of takeoff and had available safety belts. However, there were only 65 seats in the cabin which necessitated seating some of the passengers double in one seat. Although the Weight and Balance Manifest for the flight indicated a total weight of 44,500 ponds, the aircraft actually weighed 48,709 pounds, which was 3,709 pounds in excess of the 45,000 pounds certificated aircraft weight.

“At Approximately 00:10 with Alfred Cockrill acting as pilot, and John Connel as copilot, the aircraft taxied to Runway 27 where the ‘pre-takeoff check’ was accomplished at which time engines and flight controls operated normally. Takeoff was accomplished at 00:21 after the San Juan Tower had transmitted an instrument clearance to the flight authorizing it to cruise at 8,500 feet to Miami….One minute after the aircraft left the ground, and at an indicated air speed of approximately 115 miles per hour and at an indicated altitude of 250 feet, the right engine began to backfire severely and lost power. No attempt was made to feather the propeller of the right engine. An emergency was declared, and the tower cleared the flight to land on Runway 9. But, since air speed was low and altitude could not be maintained, the aircraft was flown straight ahead for a crash landing 200 yards off the shore at Punta Salinas. Immediately before impact with the water the landing lights were extended.

“During a six minute period that the aircraft remained afloat the crew pushed two uninflated life rafts into the water and furnished several passengers with life preservers. Considerable confusion existed during the ditching operation since none of the passengers had received any instruction in the location or use of emergency equipment. Of the 81 occupants, only 23 passengers and five crew members survived.

“Investigation

“The wreckage was located on the ocean floor the morning of June 7, 1949, and salvage operations were begun….The right engine and propeller had been damaged by salt wast4r and external scuffing similar to the left. However, the disassembly of this engine disclosed first, that the neoprene adapter sleeve for the carburetor and the carburetor air intake screen were covered with a heavy carbon deposit, and second, that 30 of the 36 spark plugs were type AX-LS-87 spark plugs which were not approved by the manufacturer of the spark plugs, the manufacturer of the engines, or by the U.S. Air Forces for use in the engines which were installed in this aircraft. Furthermore, the spark plug terminals for this engine were found to be oily and dirty and spark plug electrodes were found to have too much clearance.

“Of particular significance was the fact that the center electrodes in both spark plugs from the No. 4 cylinder of the right engine were found badly burned. The center electrode of the rear plug had fused with the outer electrode, and the center electrode of the front plug had burned out flush with the porcelain. In addition, the porcelain in six of the other plugs was found chipped or cracked.

“The ignition switch for the right engine was found set on the left magneto position which would have permitted, if so set during flight, only the rear spark plugs to fire. A further examination of all spark plugs in the right engine showed that the rear plugs sustained excessive heat damage while all front plugs, excepting the one in the No. 4 cylinder, showed no evidence of heat.

“On April 11, 1949, the aircraft was inspected by the Civil Aeronautics Administration and the following emergency equipment was on board the aircraft at that time. Six 10-man and one 15-man life rafts and 80 life jackets. Strato-Freight, Inc., stated that at the time of takeoff from San Juan there were ten 6-man life rafts and three 7-man rafts and 81 life jackets.

“Analysis

“AC-LS-87 type spark plugs are not approved by the manufacture of the spark plugs, the manufacturer of the engines, or by the U.S. Air Forces for the type of engines which were installed in this aircraft because the combustion chamber temperatures and pressures in such engines are too high for the satisfactory operation of this plug. In this instance, the rear spark plug in the No. 4 cylinder of the right engine operated at such a high temperature that the center electrode fused with the outer electrode….The operation of a spark plug at a temperature high enough to fuse its electrodes would result in preignition. Preignition in turn would cause backfiring through the induction system….Since severe backfiring destroys a proper fuel-air mixture, it would result in complete loss of power if sustained. All evidence found in the disassembly of the right engine indicates that this happened during this flight.

“Following the failure of the right engine, the aircraft failed to remain airborne despite the fact that the left engine was apparently developing full power, because the aircraft did not have single engine climb speed and its gross load was 3,709 pounds more than the certificated weight. Other factors contributed to this lack of single engine performance; the right propeller was not feathered, and the right cowl flaps were fully opened and the landing lights were extended, all of which would materially increase the parasitic and interference drag, further reducing the possibility of the aircraft remaining airborne under these conditions.

“As a result of this accident, and because of previous violations, the Civil Aeronautics Board by an initial decision issued October 27, 1949, Docket No. SR-2073, which became effective November 8, 1949, revoked the air carrier operating certificate of Strato-Freight, Inc. Also as a result of this accident and previous violations, the Civil Aeronautics Board by order issued January 26, 1950, Docket No. SR-2074, revoked the pilot certificate of Lee Howard Wakefield, effective February 5, 1950, for a period of six months….

“Probable Cause

“The Board determines that the probable cause of this accident was the loss of power of the right engine before the aircraft attained the optimum single engine climb sped which, together with the overloaded condition of the aircraft, resulted in it losing altitude and settling into the sea.” (Civil Aeronautics Board. Accident Investigation Report. Strato-Freight, Inc., San Juan, Puerto Rico, June 7, 1949. 2-10-1950.)

Planecrashinfo.com: “The aircraft crashed into the Atlantic Ocean during takeoff after a loss of the No. 2 engine. The loss of power in the right engine before the aircraft could attain the optimum single engine climb speed, which together with being overloaded resulted in the aircraft losing altitude and ditching into the ocean. Incorrect spark plugs installed on the No. 2 engine.” (Planecrashinfo.com.)

Sources

Aviation Safety Network. Accident Description. Strato-Freight, 07 Jun 1949. Accessed at: http://aviation-safety.net/database/record.php?id=19490607-0

Baugher, Joseph F. 1942 USAAF Serial Numbers (42-91974 to 42-110188). Oct 28, 2011 revision. Accessed 12-17-2011 at: http://www.joebaugher.com/usaf_serials/1942_5.html

Civil Aeronautics Board. Accident Investigation Report. Strato-Freight, Inc., San Juan, Puerto Rico, June 7, 1949. 2-10-1950. Accessed 9-10-2023 at; dot_33368_DS1.pdg

Eckert, William G. “Fatal commercial air transport crashes, 1924-1981.” American Journal of Forensic Medicine and Pathology, Vol. 3, No. 1, March 1982, Table 1.

Planecrashinfo.com. “1949…Accident Details…Strato Freight…San Juan-Miami…June 7, 1949. Accessed at: http://www.planecrashinfo.com/1949/1949-26.htm

Text content

1949 — June 7, Strato-Freight Inc. plane crash after takeoff, San Juan, PR to Miami — 53