6-103
1946-MAR-03 · Thing Mountain, California

American Airlines — Flight 6-103

American Airlines Flight 6-103 crashed into the eastern slope of Thing Mountain during its final leg from El Paso to San Diego, killing all 27 people on board. The aircraft was operating a transcontinental multi-stop service and was flying in instrument conditions when it descended below the required altitude to clear terrain. At the time, it was the deadliest accident in the history of American commercial aviation. The exact crash site remained undocumented for decades until it was rediscovered by researchers in 2015.

Aircraft
Douglas DC-3-277B
Registration
NC21799
Phase
Cause
Souls on Board
27
Fatalities
27
Origin → Dest
New York City, New York → San Diego, California
Report

Investigation Summary

The flight originated in New York on March 2, 1946, and proceeded through several scheduled stops without incident. After a crew change in El Paso and a brief stop in Tucson, the aircraft departed for San Diego at 05:59 PST. The flight crew maintained regular radio contact, reporting their position over El Centro at 8,000 feet at 07:53 PST. Shortly thereafter, Los Angeles air traffic control issued a clearance to maintain 8,000 feet, but the San Diego radio station was unable to relay this message as the aircraft failed to respond to further calls. The wreckage was spotted later that afternoon by a Navy aircraft at an elevation of 4,870 feet on Thing Mountain, approximately 50 miles east of San Diego. The investigation by the Civil Aeronautics Board (CAB) found that the aircraft had struck the mountain while in a normal cruising attitude, indicating the pilots were likely unaware of their proximity to the terrain. While the CAB determined the pilot permitted a descent into instrument conditions below the safe minimum altitude, the specific reason for this descent could not be established due to the lack of flight recorders and the total destruction of the aircraft.

Final Conclusions

The Civil Aeronautics Board determined the probable cause was the action of the pilot in descending, or permitting a descent to be made, into instrument conditions to an altitude below that required to maintain clearance over Thing Mountain. The reason for the descent has not been determined.

Video Analysis

No video analysis linked for this case file yet.

Airframe & Maintenance

Airframe Hours
16,322

Crew Experience

Captain

Total hours
6,793
On type
4,235

Samuel Edward Stoner, age 30.

First Officer

Total hours
3,300
On type
2,300

Emmett Edward Baker Jr., age 25. 1,000 hours were obtained in the Navy.

Systems & Failure Modes

i

Radio Navigation

The crew used routine position reports over Casa Grande, Gila Bend, Yuma, and El Centro to track their progress along the airway.

i

Altimeter

The aircraft was cleared for 8,000 feet but was found at 4,870 feet, indicating a significant unintended or unrecognized loss of altitude.

Interesting Facts

  • 01The accident was the deadliest American airliner crash at the time of its occurrence.
  • 02The aircraft had accumulated 16,322 flying hours since its first flight in 1940.
  • 03While the wreckage was partially cleared in 1946, the exact GPS location of the site remained undocumented until its rediscovery in 2015.
  • 04The 27 fatalities consisted of 3 crew members and 24 passengers (22 adults and 2 infants).
  • 05The impact occurred approximately 50 miles east of the destination in San Diego.

Safety Actions & Advisories

Altitude Clearance Enforcement

The investigation emphasized the necessity of maintaining cleared altitudes in instrument conditions, particularly when traversing mountainous terrain where minimum safe altitudes are critical for obstacle clearance.

Location

Thing Mountain, California · 32.8281, -116.5267

Case File History

  1. New evidenceUpdated findings.
  2. New evidenceUpdated event timeline, findings and safety actions.

Related Cases

Case ID · aa6-1946Last updated · Filed

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