On November 1, 1988, a Vickers Vanguard, flight 435, experienced a catastrophic accident at Basel/Mulhouse Airport during an approach to the BN beacon. The aircraft, carrying 108 occupants and 37 survivors, was cleared to continue to the NDB. Weather conditions were characterized by poor visibility ? cloud base at 120 meters and a 700-foot runway visual range. The flight crew, navigating on a charter flight from Bristol (BRS) to Basle Mulhouse (BSL), initiated a 90-degree left turn to finals for the runway. At 09:56, the crew reported at 2500 feet, followed by a position report of the MN beacon at 09:57:40. Upon reaching the BN beacon, the crew cleared to descend to 2500 feet and was instructed to report over the MN beacon. The crew then turned outbound, reporting at the MN beacon again for another approach. The crew reported overhead the BN beacon again, which was actually at the airfield, parallel to the ILS localizer beam. After 1.5 minutes, the aircraft began to overshoot, correctly making an initial turn to the west. The crew, now flying well south of the field, were instructed to report back over the MN beacon. When reporting over the MN beacon again, before it would have to turn left for finals, the plane was in fact overhead the BS beacon, a beacon located to the south of runway 16. At 10:11:25, the crew reported over the BN beacon on finals and was cleared to land. In fact, the plane was now flying 3 miles south of the field and 1 mile west of the extended centerline. Two miles further on Basle ATC asked the crew ‘Are you sure you are over the BN?’ The captain replied ‘I think I’ve got a spurious indication. We are on the LO… on the ILS now, sir’. Half a minute later, the captain radioed ‘BN is established on localizer and glide path; the ADF’s all over the place in this weather.’ The last radio contact was when the captain reported at 1400 feet, to which ATC replied that the flight was probably to the south of the airport. At 10:13, the plane brushed against a wooded range of hills and crashed 15 km from the airport. The aircraft disintegrated, except for the tail section, with most of the survivors found. PROBABLE CAUSE: A loss of orientation during two ILS approaches carried out under instrument flight conditions. The following factors contributed to the occurrence of the accident: 1) inadequate navigation, above all imprecise initiation of final approach as regards height and approach center-line; 2) confusion of aids; and 3) insufficient checking and comparison of navigational aids and instrument readings (cross and double checks). The poor reception of HT medium wave beacons and technical defects in LOC receiver No.1 and glide slope receiver no.2 made the crew’s navigational work more difficult.On November 1, 1988, a Vickers Vanguard, flight 435, experienced a catastrophic accident at Basel/Mulhouse Airport during an approach to the BN beacon. The aircraft, carrying 108 occupants and 37 survivors, was cleared to continue to the NDB. Weather conditions were characterized by poor visibility ? cloud base at 120 meters and a 700-foot runway visual range. The flight crew, navigating on a charter flight from Bristol (BRS) to Basle Mulhouse (BSL), initiated a 90-degree left turn to finals for the runway. At 09:56, the crew reported at 2500 feet, followed by a position report of the MN beacon at 09:57:40. Upon reaching the BN beacon, the crew cleared to descend to 2500 feet and was instructed to report over the MN beacon. The crew then turned outbound, reporting at the MN beacon again for another approach. The crew reported overhead the BN beacon again, which was actually at the airfield, parallel to the ILS localizer beam. After 1.5 minutes, the aircraft began to overshoot, correctly making an initial turn to the west. The crew, now flying well south of the field, were instructed to report back over the MN beacon. When reporting over the MN beacon again, before it would have to turn left for finals, the plane was in fact overhead the BS beacon, a beacon located to the south of runway 16. At 10:11:25, the crew reported over the BN beacon on finals and was cleared to land. In fact, the plane was now flying 3 miles south of the field and 1 mile west of the extended centerline. Two miles further on Basle ATC asked the crew ‘Are you sure you are over the BN?’ The captain replied ‘I think I’ve got a spurious indication. We are on the LO… on the ILS now, sir’. Half a minute later, the captain radioed ‘BN is established on localizer and glide path; the ADF’s all over the place in this weather.’ The last radio contact was when the captain reported at 1400 feet, to which ATC replied that the flight was probably to the south of the airport. At 10:13, the plane brushed against a wooded range of hills and crashed 15 km from the airport. The aircraft disintegrated, except for the tail section, with most of the survivors found. PROBABLE CAUSE: A loss of orientation during two ILS approaches carried out under instrument flight conditions. The following factors contributed to the occurrence of the accident: 1) inadequate navigation, above all imprecise initiation of final approach as regards height and approach center-line; 2) confusion of aids; and 3) insufficient checking and comparison of navigational aids and instrument readings (cross and double checks). The poor reception of HT medium wave beacons and technical defects in LOC receiver No.1 and glide slope receiver no.2 made the crew’s navigational work more difficult.