Date:	Saturday 2 August 1947
Time:	14:45
Type:	Avro 691 Lancastrian C.3
Owner/operator:	British South American Airways - BSAA
Registration:	G-AGWH
MSN:	1280
Year of manufacture:	1945
Total airframe hrs:	1655 hours
Engine model:	Rolls-Royce Merlin
Fatalities:	Fatalities: 11 / Occupants: 11
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	Tupungato Mountain -   Argentina
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Morón Air Base, BA (SADM)
Destination airport:	Santiago-Los Cerrillos Airport (ULC/SCTI)
Investigating agency:	JIAAC
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
The Avro 691 Lancastrian 3 passenger plane, G-AGWH, was completing the last leg from Buenos Aires, Argentina to Santiago, Chile of a flight that originated in London, U.K. The flight from London to Buenos Aires was carried out in a York aircraft and at Buenos Aires the customary transfer was made to a Lancastrian to facilitate the crossing of the Andes Mountains.
The flight plan was made out for the route Buenos Aires-Santiago via Mendoza. The amount of fuel carried was 1,380 gallons, giving an estimated duration of 6 hours and 30 minutes. The estimated time of the flight was 3 hours 45 minutes. By keeping to the
flight plan and arriving over Mendoza at 18,000 feet the distance of 526 nautical miles from Buenos Aires to Mendoza should have taken 3 hours 12 minutes. The remaining distance of 106 miles from Mendoza to Santiago should have taken 33 minutes at proposed height of 26,000 feet. The aircraft departed Buenos Aires at 13:46 hrs UTC. Last contact with the flight was at 17:41 when the Chilean Air Force radio operator at Santiago when the flight stated an ETA of 17:45, ending with "STENDEC". This was repeated twice when the radio operator queried the call since he did not understand "STENDEC". Investigators were not able to find out what the radio operator of G-AGWH meant by "STENDEC".

In 1998, two Argentine mountaineers climbing Mount Tupungato, about 50 miles (80 km) east of Santiago, found the wreckage of a Rolls-Royce Merlin aircraft engine, along with twisted pieces of metal and shreds of clothing, in the Tupungato Glacier at an elevation of 15,000 ft (4,600 m). In 2000, an Argentine Army expedition found additional wreckage, including a propeller and wheels that appeared to have belong to G-AGWH.

Cause:
During a scheduled passenger flight, collision with the mountain, when the crew started a descent before the expected position, in IMC conditions, due to an incorrect calculation of the navigation speed.

Contributing factors:
Pilot in command:
Probable lack of knowledge of the weather condition "Mountain Wave" and jet stream
Adoption of the Central or Direct Route with bad weather conditions.

Meteorology:
Atmospheric disturbance known as Mountain Wave associated with a jet stream

U.K. AIB investigation report dated 22 December 1947
The Civil Aircraft Registers of Great Britain
Star Dust Falling / J.Rayner

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