Background
On 20 January 1992, an Airbus A320, registered F-GGED, operated by Air Inter as flight ITF 148 DA, conducted a scheduled night service from Lyon-Satolas to Strasbourg-Entzheim. The aircraft carried 90 passengers, two flight crew, and four cabin crew. The flight proceeded without reported issues until the approach phase.
Flight and Communication
Runway 05 was in use at Strasbourg. After listening to ATIS, the crew planned an ILS approach for runway 23 followed by visual maneuvering to runway 05. Reims Air Traffic Control cleared the aircraft to Flight Level 70 near the ANDLO waypoint. At 18:09, Strasbourg Approach Control contacted the aircraft at Flight Level 150, about 22 nautical miles from STR VOR. Control cleared descent to 5,000 feet QNH and later cleared a VOR-DME approach to runway 05 after the crew reported passing ANDLO. However, the aircraft's altitude and speed precluded a direct approach, so the crew informed control of their intention to perform an ILS approach for runway 23 with visual maneuvering. Control noted a delay due to three departing aircraft. The crew then opted for a full VOR-DME procedure for runway 05. Control suggested radar guidance back to ANDLO, which the crew accepted.
Approach and Descent
The controller directed a left turn to heading 230 for an outbound track parallel to the approach axis, then a reciprocal turn toward ANDLO. At 18:19, the controller advised the crew they were abeam ANDLO and cleared them for final approach. The aircraft began its descent approximately 11 nautical miles from STR VOR, the procedure-required distance. Thirty seconds later, the controller requested a call when passing STR, which the crew acknowledged—the last communication.
Accident and Rescue
The wreckage was discovered at 22:35 on a slope of Mont "La Bloss" at an elevation of approximately 800 meters (2,620 feet), about 0.8 nautical miles left of the approach path and 10.5 nautical miles from the runway threshold. Five crew members and 82 passengers were killed; nine occupants, including one crew member, were rescued.
Probable Cause
The investigation concluded that the crew was late in modifying approach strategy due to communication ambiguities with air traffic control. They relaxed their attention during radar guidance and did not adequately anticipate aircraft configuration for landing. The key event was the start of descent at the procedure-required distance but at an abnormally high vertical speed of 3,300 feet per minute instead of approximately 800 feet per minute, which the crew failed to correct. Possible reasons for the high descent rate include confusion in vertical modes or incorrect selection of target value; a FCU failure was considered highly unlikely. The crew's lack of notice of the incorrect trajectory was attributed to several factors: below-average performance with insufficient cross-checks, minimal crew communication, ergonomic design of vertical trajectory display, late strategy change due to communication ambiguity, relaxation of attention during radar guidance followed by a workload peak, focus on horizontal navigation, and absence of a GPWS. The commission also considered that the ergonomic design of autopilot vertical mode controls could have contributed to the accident situation.