Flight Summary
On 2 June 2012 at 1828 hours, Allied Air Ltd Flight DHV 111, a Boeing 727-221 cargo aircraft registered 5N-BJN, departed Murtala Muhammed International Airport in Lagos, Nigeria, en route to Kotoka International Airport in Accra, Ghana, with a further destination of Abidjan. The flight crew consisted of four members. While taxiing, the Flight Engineer observed an illuminated CSD amber caution light, which was disconnected with the Captain's permission.
Accident Sequence
The flight was conducted under Instrument Flight Rules (IFR) in turbulent conditions, cruising at 280 knots, the recommended turbulence speed. During descent into Accra, the aircraft was cleared by Accra Approach to Flight Level 50, then to 2,000 feet, and subsequently instructed to climb to 3,000 feet due to high ground. The Captain flew an Instrument Landing System (ILS) coupled approach until visual with the runway, disconnecting the autopilot at 500 feet. Immediately after, the aircraft encountered heavy IMC conditions with rain.
The approach became unstable at a high speed of 167 knots. The aircraft landed with a wind of 050/15 knots at 154 knots, approximately 5,807 feet from the start of Runway 21, in nil visibility. The crew deployed thrust reversers and applied normal and emergency pneumatic brakes, but these were ineffective. The nose gear remained up, and speed brakes were not deployed. The crew reported seeing red lights rushing towards them after main wheel touchdown. The nose gear did not contact the ground until the aircraft had passed the airport perimeter fence.
A Lufthansa flight (DLH 566) that landed earlier at 1902 hours reported a wind of 050/15 knots and visibility of 3,800 meters in rain. The DLH crew observed the Allied Air aircraft appear to land at very high speed. The tower controller and a marshaller in a follow-me vehicle noted the landing occurred between the first and second intersections. The Flight Data Recorder (FDR) indicated the aircraft touched down at 150 knots and 1.6 G, 5,807 feet from the beginning of Runway 21 and 4,000 feet from the threshold of Runway 03. The full length of Runway 21 is 3,403 meters (11,162 feet for take-off), but the available landing distance was 2,990 meters (9,807 feet). The runway surface was reported as good by the DLH crew.
Aftermath
The aircraft overran the runway, destroying threshold and approach lights on Runway 03, knocking out the ILS localizer transmitter structure, and breaching the airport perimeter wall. It crossed Giffard Road and collided with a passenger mini bus, killing all ten persons on board. The aircraft uprooted a tree before stopping in an open space near El-Wak Sport Stadium, 1,171 feet (350 meters) from the threshold of Runway 03, heading 215° southwest. The leading edge of the right wing was extensively damaged, and a taxi cab was grazed by debris. The aircraft and mini bus were destroyed. The four crew members sustained minor injuries.
At 1910 hours, the Rescue and Fire Fighting Service (RFFS) was alerted; firemen arrived at the crash site nine minutes later. The airport was closed for 45 minutes for runway inspection, during which no pool of water was found. Approximately one hour after the overrun, the airport reopened to traffic.
The Technical Log Book contained no records of deferred defects. The Captain stated that windshield wipers were switched on during landing but were unable to clear the rain. Investigation revealed the wipers were only three-quarters switched on.
Investigation Findings
The official probable cause of the accident was determined to be the Captain's decision to continue the landing instead of aborting at the missed approach point, particularly when he could hardly see through the windshield and did not know his position on the runway due to rain and tailwind components. Contributory factors included: the Captain disconnecting the autopilot and flying manually in an unstable approach; landing 4,000 feet from the threshold of Runway 03 (6,060 feet from Runway 21) and being unable to stop within the available distance; landing with a tailwind of 15 knots exceeding the maximum allowable 10 knots; crew fixation on tracking the localizer rather than observing threshold and runway edge lights; and the Captain failing to deploy speed brakes on landing.