Investigation Summary
The flight was a seasonal tourist charter carrying British vacationers to Yugoslavia. During the descent, the Ljubljana controller provided the crew with both QNH (1011 mb) and QFE (968 mb) pressure settings. The 43 mb difference between these two values represented approximately 1,160 feet of altitude. Although the crew acknowledged the information, they failed to update the Captain's altimeter to the QFE setting. Consequently, while the pilots believed they were at the correct procedural altitudes relative to the runway, they were actually over 1,100 feet lower. The approach was conducted on a moonlit night with good visibility, which paradoxically may have led to a reduction in crew concentration and a reliance on visual cues that were deceptive due to the sloping terrain and uniform forest cover. The lack of a cross-check between the two pilots' altimeters, as required by the airline's operations manual, allowed the error to persist until impact.
Final Conclusions
The official investigation concluded the primary cause was the pilot in command's failure to set the altimeter to the QFE of 968 mb. The crew flew the entire approach as if the QFE was set, leading to an altitude approximately 1,160 feet lower than intended. Contributing factors included the crew's failure to perform mandatory altimeter cross-checks and the deceptive visual effect of the runway slope and tree-covered terrain, which prevented the pilots from recognizing their dangerously low altitude despite the clear weather.
Photographic Evidence (1)
Video Analysis
Britannia Airways Flight 105 Aftermath Footage | 1 September 1966 Ljubljana, Slovenia — Historical footage and accident description of the Britannia Airways Flight 105 crash near Ljubljana, which remains the deadliest aviation accident in Slovenian history.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
First Officer
Systems & Failure Modes
Altimeter
Primary flight instrument used to measure altitude based on atmospheric pressure; incorrect setting led to a 1,000-foot vertical error.
Instrument Landing System (ILS)
A precision approach system that the crew requested and ATC confirmed was operational, though the flight was conducted under visual conditions.
Interesting Facts
- 01The accident is the deadliest aviation disaster to occur on Slovenian soil.
- 02The aircraft was not equipped with a Flight Data Recorder as they were not mandatory in 1966.
- 03The co-pilot's altimeter was found after the crash set to 1005.5 mb, while the Captain's was expected to be at 968 mb.
- 04Nineteen people survived the initial impact and subsequent fire.
- 05The crash site was located 2.8 km southeast of the runway 31 threshold.
Safety Actions & Advisories
Altimeter Cross-Check Procedures
The investigation emphasized the critical importance of following operations manual instructions regarding the cross-checking of the two pilots' altimeters during approach.