Investigation Summary
The investigation into Flight 435 revealed a staggering history of pilot incompetence, particularly regarding Captain Anthony Dorman. Dorman had been dismissed from the Royal Canadian Air Force for lack of aptitude and had failed his UK instrument rating test eight times before finally passing on his ninth attempt. On the day of the accident, heavy snow and technical issues with the aircraft's navigation equipment exacerbated the crew's poor performance. The aircraft's No. 1 localizer receiver and No. 2 glideslope receiver were found to have technical defects, and the medium-wave NDB (Non-Directional Beacon) reception was poor due to the weather. However, the primary failure was the crew's inability to cross-check their position. They reported passing the BN beacon when they were actually over the airfield, and later reported being established on the ILS while they were miles south of the runway, flying away from the airport into the Jura Mountains.
Final Conclusions
The Swiss Federal Commission of Inquiry concluded the accident was caused by a total loss of orientation during two ILS approaches in instrument meteorological conditions. Contributing factors included inadequate navigation, imprecise initiation of the final approach, and the confusion of navigational aids. The crew failed to perform necessary cross-checks of their instrument readings. Technical defects in the navigation receivers and poor NDB reception in the wintry conditions further complicated the crew's ability to maintain situational awareness.
Photographic Evidence (1)
Video Analysis
Invicta International Airways Flight 435 Aftermath Footage — Historical news footage and survivor interviews following the 1973 crash of a Vickers Vanguard near Hochwald, Switzerland.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Pilot-in-command for the accident leg. Had failed instrument rating 8 times.
Co-pilot
Also held the rank of Captain; handled radio communications during the approach.
Systems & Failure Modes
ADF (Automatic Direction Finder)
The crew reported the ADF needles were 'all over the place' due to weather interference and technical defects.
ILS (Instrument Landing System)
Technical defects were found in the No. 1 localizer receiver and No. 2 glideslope receiver, providing unreliable data during the approach.
NDB (Non-Directional Beacon)
The crew misidentified or missed several NDBs (BN and MN) used for navigating the Basel terminal area.
Interesting Facts
- 01The flight was a charter carrying members of the Axbridge Ladies Guild and other local social groups on a shopping trip.
- 02Captain Anthony Dorman had failed his instrument rating test eight times before succeeding on the ninth attempt.
- 03The accident remains the deadliest aviation disaster to occur on Swiss soil.
- 04The aircraft was a Vickers Vanguard, a large four-engine turboprop that was already largely obsolete by 1973.
- 05Most of the 37 survivors were seated in the tail section, which remained relatively intact after the aircraft somersaulted.
Safety Actions & Advisories
UK Regulation Tightening
As a result of the crash and the discovery of the Captain's poor training record, the United Kingdom introduced tougher regulations regarding pilot licensing and instrument rating oversight.