What happened
On the evening of November 7, 1969, a Beech D95A Travelair, registration G-ATLX, departed Biggin Hill, United Kingdom, for a private flight to Switzerland. The aircraft was carrying the pilot and his bride as the sole occupants.
During the approach to Zurich Airport, the aircraft was operating under instrument flight rules in conditions characterized by heavy fog and low visibility. While established on the ILS approach for runway 16, the aircraft descended significantly below the glideslope. At approximately 18:12, the aircraft collided with a line of trees near Stadel-Windlach, roughly 9 km from the runway threshold. The impact caused the aircraft to crash into a field, where it subsequently caught fire. The collision resulted in two fatalities.
The investigation
Investigators examined the wreckage, radio communications, and meteorological data. The investigation confirmed that the aircraft's engines were running at moderate power at the time of impact and the landing gear was extended and locked. While the wreckage was heavily damaged by the impact and fire, the primary altimeter was recovered in relatively good condition, showing a setting of 1002.0 mb.
Air traffic control records and radio transcripts showed that the pilot had communicated normally and appeared relaxed, confirming he was established on the ILS. However, radar contact was lost approximately 5 nautical miles from the runway threshold. A witness, a captain from a Lufthansa flight, observed the aircraft's lights and noted that it appeared to be flying below the established glidepath.
Findings
- The aircraft flew significantly below the ILS glidepath.
- The pilot likely misjudged his altitude due to an unfamiliar altimeter setting.
- There was a possibility that the glidepath indicator was either not activated or was improperly tuned, causing the needle to remain centered and providing a false sense of being on course.
- The pilot's previous landings at Zurich had been conducted during the day under Visual Flight Rules (VFR), which may have contributed to a false sense of security during this difficult night instrument approach.
- The investigation noted that the use of Precision Approach Radar (PAR) might have prevented the accident.