Aviaco Bristol 170 EC AEG accident
Bristol 170 Freighter Mk21 · Controlled flight into terrain due to severe turbulence
From Bilbao Airport (BIO) to Adolfo Suárez Madrid–Barajas Airport (MAD)
Event
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- Event fatalities
- 22 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- Unknown
- Survivors
- 10
- InjuriesFatal: death within 30 days. Serious: over 48 hours in hospital within a week, most broken bones, severe bleeding, nerve or organ damage, or serious burns. Minor: anything less. Glossary
- 10
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
Bristol 170 Freighter Mk21
- Aircraft type
- Bristol 170
- Category
- Airplane · from aircraft type
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- EC-AEG
- Operator
- Aviaco
- Onboard fatalities
- 22
- Route
- From Bilbao Airport (BIO)To Adolfo Suárez Madrid–Barajas Airport (MAD)
Approximate · Coordinates from the Wikipedia article; not checked against an investigation report.
From the Wikipedia article
On 4 December 1953, a Bristol 170 model aircraft, registration EC-AEG, belonging to the airline Aviaco and operating the scheduled Bilbao-Madrid route, crashed into the peak of La Cebollera, near the Somosierra pass, due to severe turbulence produced by orographic clouds, which can generate strong turbulence known as mountain waves; 22 of its 32 occupants died.
Accident
On 4 December 1953, one of the six Bristol 170/171 Freighter Mk21s owned by the former company Aviaco, founded in 1948 in Bilbao, registered as EC-AEG, was making its scheduled flight between the cities of Bilbao and Madrid.
It departed Bilbao Airport at four in the afternoon and was scheduled to arrive at Madrid-Barajas Airport at a quarter past five that same day.
The flight crew operating the aircraft on the day of the accident consisted of the captain, Mr. Cañete, the second pilot, Air Force Captain Barsen Garcia-Lopez, the flight mechanic Mr. Gonzalo Fernandez Soto and the radio operator Mr. Romero. In charge of the passengers was the stewardess Jesusa Terradillos, who had been the first stewardess of the airline Aviaco.
The aircraft was flying in very adverse weather conditions when it made its last radio transmission reporting that they were five minutes' flying time from the Somosierra Pass, which was the last mountainous area they had to overfly before beginning the descent towards their final destination, Madrid-Barajas Airport.
The aircraft was caught by severe turbulence caused by orographic clouds, which generate an atmospheric phenomenon known as a mountain wave that has very strong downdrafts associated with it and a great deal of associated turbulence.
Caught in this severe turbulence, the aircraft struck the peak of La Cebollera and caught fire, thus killing 22 of its 32 occupants.
Four of the five crew members who were in the front part of the aircraft, in the cockpit, survived, the stewardess Jesusa Terradillos being the only fatality among the crew, together with twenty-one passengers.
Among the dead was Rafael Escudero Etxebarria, a player who had played for Athletic Club and who held a position on the board at the time of the accident.
Investigation and cause
Causes
Although no official technical report on the causes of the accident was drawn up, everything seems to indicate that meteorological causes were what led the aircraft to experience controlled flight into terrain, as they were drawn in by severe turbulence that made them descend suddenly and without being able to gain altitude to clear the peak of La Cebollera, which is at a height of about 2000m (metres).
Captain Cañete, who was acting as first pilot on that flight, sent a letter years later, included in the book Meterología aplicada a la aviación, explaining what was experienced, from the meteorological point of view, in the aircraft's cockpit during the flight and the subsequent accident. From what can be read in his letter, it seems evident that the very severe turbulence he describes was produced by a mountain wave, an atmospheric phenomenon very little known in the year 1953.
In it he relates that the takeoff at Bilbao Airport was very turbulent, with gusting winds of up to almost 40kt (knots) and with severe turbulence until reaching 4300ft (feet) of altitude, while they continued climbing to their cruising altitude, which was about 7000ft.
As related in his letter, when they were about five minutes' flying time from the Somosierra (Madrid) radio beacon, in a layer of cloud, they began to experience turbulent updrafts and downdrafts that made them lose control of the aircraft, reaching a rate of descent of 45ft (feet) per second, and despite trying to maintain altitude using all the available engine power, the aircraft was unable to gain speed. Faced with an imminent possible stall, Captain Cañete relates that he had to lower the aircraft's nose to be able to gain speed, and after descending almost 2500ft (feet), they remained immersed in strong currents until they finally struck the terrain.
Translated into English with AI assistance from the Spanish Wikipedia article “Accidente Bristol 170 EC AEG de Aviaco” (revision 168721492, retrieved 2026-09-19) by its authors, under CC BY-SA 4.0. Extracted as plain text: references, tables, images and some sections are left out; the translation may contain errors, and long articles were cut to their first 700 words. Read the article
Sources
Spanish Wikipedia article: Accidente Bristol 170 EC AEG de Aviaco
- Translation
- Into English with AI assistance; names of linked operators and aircraft types from Wikidata. It may contain errors.
- Revision
- 168721492 · 2025-07-29 · retrieved 2026-09-19
- Wikidata
- Q104848941
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
Where each value comes from
- Record
- es Wikipedia article "Accidente Bristol 170 EC AEG de Aviaco" (page 9755545, revision 168721492), translated into English with AI assistance
- Date
- Wikipedia infobox: date
- Place and country
- Wikipedia infobox: site
- Map position
- Wikipedia article coordinates
- Aircraft, operator and route
- Wikipedia infobox: aircraft type, registration, operator, origin and destination; route airports from the linked airport articles' Wikidata codes (OurAirports)
- Operation
- operator is an airline according to Wikidata
- Fatalities
- Wikipedia infobox: aircraft fatalities
- Ground fatalities
- not stated in the Wikipedia infobox
- Summary
- Wikipedia infobox: summary
Source notes (1)
- Wikipedia · Facts from the Spanish Wikipedia article's infobox, translated into English with AI assistance, not checked against an investigation report. Independent review pending.