Balkan Bulgarian Airlines Antonov An-24 LZ-ANA accident
Antonov An-24B · Stall on takeoff, plunge into river (icing)
From Sofia Airport (SOF) to Varna Airport (VAR)
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
- 3 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- Unknown
- Survivors
- 42
- 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
- Unknown
- 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
Antonov An-24B
- Aircraft type
- Antonov AN-24
- 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
- LZ-ANA
- Operator
- Balkan Bulgarian Airlines
- Onboard fatalities
- 3
- Route
- From Sofia Airport (SOF)To Varna Airport (VAR)
Cause areas
- Aircraft › Aircraft handling/service
- Aircraft › Fluids/misc hardware
- Aircraft › Aircraft oper/perf/capability
From the investigation findings the Wikipedia article reports, sorted into the NTSB's cause areas with AI assistance.
Not plotted · Not plotted: the Wikipedia article gives no coordinates, and its site names no town or airport that matches exactly.
From the Wikipedia article
The accident of the Balkan Bulgarian Airlines Antonov An-24 LZ-ANA occurred on 2 November 1975 on a domestic scheduled Balkan Bulgarian Airlines flight from Sofia to Varna. On this day an Antonov An-24B carrying 42 passengers and three crew members stalled on takeoff in wintry conditions and crashed into the Iskar River. 42 occupants survived the accident, but the first officer and two passengers were killed.
Accident sequence
Heavy snow was falling at Sofia Airport in Bulgaria when the Antonov An-24 was being prepared for the evening flight to Varna. The aircraft was de-iced and taxied to the starting point of runway 10. However, the runway remained closed for some time, as snow-clearing vehicles had been sent out along the runway for winter maintenance.
After the runway had been cleared, the crew was given takeoff clearance. The An-24 was unable to gain height after takeoff and crashed into a ditch of the Iskar River approximately two minutes after takeoff, 990 metres southeast of the runway. No fire broke out. The first officer was killed and two passengers drowned in the water. 18 passengers were injured, four of them seriously. The rescue of the passengers took 40 minutes.
Investigation and cause
Causes
During the investigation the commission found a number of violations. After the aircraft's last landing at Sofia Airport, no protective plugs had been fitted at the points provided for them. They protect the engines against the ingress of water. The aircraft was treated with a mixture of water and de-icing fluid. However, this was done with the Bulgarian mixture "Ledogon" instead of the English "Kilfrost" or the Soviet "Arktis". In addition, the product was incorrectly diluted by the service personnel on that day. As a result, the aircraft was sprayed with 75 % water and only 25 % Ledogon. The holdover time for the de-icing had expired during the snow-clearing work, and the renewed de-icing of the wings, which had meanwhile again been contaminated by snow and ice and which had thereby become necessary, was not carried out. The crash occurred because the contamination by ice crystals impaired the aerodynamic properties, which led to the stall on takeoff.
Translated into English with AI assistance from the German Wikipedia article “Flugunfall der Antonow An-24 LZ-ANA der Balkan Bulgarian Airlines” (revision 237030478, 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
German Wikipedia article: Flugunfall der Antonow An-24 LZ-ANA der Balkan Bulgarian Airlines
- Translation
- Into English with AI assistance; names of linked operators and aircraft types from Wikidata. It may contain errors.
- Revision
- 237030478 · 2023-09-04 · retrieved 2026-09-19
- Wikidata
- Q98081344
- 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
- de Wikipedia article "Flugunfall der Antonow An-24 LZ-ANA der Balkan Bulgarian Airlines" (page 11407254, revision 237030478), translated into English with AI assistance
- Date
- Wikipedia infobox: date
- Place and country
- Wikipedia infobox: site
- Map position
- none
- 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 named as an airline in the infobox
- Fatalities
- Wikipedia infobox: aircraft fatalities
- Ground fatalities
- not stated in the Wikipedia infobox
- Summary
- Wikipedia article lead
Source notes (2)
- Wikipedia · Facts from the German Wikipedia article's infobox, translated into English with AI assistance, not checked against an investigation report. Independent review pending.
- The German article's text once gives 2 November 1975; its infobox and cited Aviation Safety Network record give 22 November 1975, used here.