7 November 1996
| ATC error, and pilot misjudgment after TCAS warning|
Murtala Muhammed International Airport
Faucett Flight 251, 1996 Air Africa crash, Hemus Air Flight 7081, Vnukovo Airlines Flight 2801, United Express Flight 5925
ADC Airlines Flight 86 was a Nigerian domestic flight operated by ADC Airlines from Port Harcourt to Lagos. On 7 November 1996 the crew of the Boeing 727-200 operating the flight lost control of the aircraft while avoiding a mid-air collision on approach; the aircraft crashed inverted at a very high speed, killing all 144 passengers and crew on board.
ADC Airlines Flight 86 Wikipedia
Flight 86 was en route to Lagos airport at flight level (FL) 240 (approximately 24,000 ft (7,300 m) altitude). At the same time an aircraft operated by Triax was on its way from Lagos to Enugu at FL160. The Lagos Air Traffic Controller cleared the crew of Flight 86 to descend, but erroneously thought that he had earlier cleared Flight 86 to descend to 10,000 ft (3,000 m) and that it was below the Triax aircraft. The descent from FL240 caused Flight 86 to conflict with the Triax flight at FL160. The traffic collision avoidance system (TCAS) sounded an alert but when the crew took evasive action they overcompensated and it rolled too far; the pilots lost control and within sixteen seconds the aircraft was upside down and diving towards the ground at near-Mach 1 speed. The inverted aircraft disintegrated on impact near Imota (Ejirin) at 17:05 local time.