Sosoliso Airlines Flight 1145

Sosoliso Airlines Flight 1145 (SO1145/OSL1145) was a scheduled Nigerian domestic passenger flight from Nigeria's capital of Abuja (ABV) to Port Harcourt (PHC). At approximately 14:08 local time (13:08 UTC) on 10 December 2005, it crash-landed at Port Harcourt International Airport. The aircraft, a McDonnell Douglas DC-9-32 with 110 people on board, slammed into the ground and burst into flames. Immediately after the crash, seven survivors were recovered and taken to hospitals, but only two people survived.

It was the second air disaster to occur in Nigeria in less than three months, after Bellview Airlines Flight 210, which crashed on 22 October 2005 for reasons unknown, killing all 117 people on board. It was the company's first and only fatal accident.

An investigation carried out by Nigeria's Accident Investigation Bureau attributed the crash to the pilots' decision to keep descending past the minimum decision altitude even though they did not have the runway in sight. Contributing factors include the crew's delayed decision to execute a go-around, improper procedure being followed when it was executed, adverse weather conditions caused by microburst-induced windshear and thunderstorms, and the absence of runway lighting.

Accident

Flight 1145 was a scheduled domestic passenger flight from Nigeria's capital Abuja to Port Harcourt, the capital of Rivers State. The aircraft departed from Nnamdi Azikiwe International Airport at 12:25 p.m with 103 passengers and 7 crew members, with Captain Adebayo (48) as the pilot who was in control of the aircraft and First Officer Andan (33) as his co-pilot. The flight was uneventful until its final approach in Port Harcourt.

About 90 mi from the airport, the aircraft contacted controller for initial descent clearance and was cleared by controller to descent to 16,000 ft. The aircraft continued its descent until 13:00, when the crew asked the controller for the weather condition at the airport. The controller told the crews that there was no precipitation and that there were scattered cumulonimbus clouds in the area. The crew acknowledged the report and continued their descent.

At 6 nmi from the airport, on 13:04 p.m, the aircraft had been established on the glide-slope. At this time, the aircraft had entered adverse weather condition with headwind and tailwind. The flight crews then requested clearance to land at Runway 21. The controller then contacted Flight 1145 and advised that there was a possibility of rain in the airport. The controller then cleared the aircraft to land at Runway 21, but warned the pilots that the runway could be slightly wet, indicating that hydroplaning was a possibility. The flight crews then acknowledged this message.

Flight 1145 then descended until it had passed the decision altitude of 307 ft. As the rain intensified, the visibility deteriorated. The unlit runway further aggravated the situation. Unable to make out the unlit runway through the rain, Captain Adebayo called for a go around (missed approach) at an altitude of about 200 ft or approximately 120 ft above the ground. This call was made about 100 ft below the decision altitude. His decision, however, was too late as Flight 1145 was already too low for a go-around. The "TOO LOW-GEAR" warning then sounded and the flight crews tried to add more thrust. The flight crews had not managed to prepare the aircraft's configuration in a timely manner and the aircraft kept descending.

The DC-9 then slammed onto the grass strip between the runway and the taxiway. It then slid and struck a concrete drainage culvert located near the runway. The collision then disintegrated the aircraft. The tail section was immediately destroyed and the engine was lodged into the drainage. As it broke up, the fuel spilled and the aircraft burst into flames. The fuselage and the cockpit, now in flames, continued to slide for few hundreds metres before it finally came to rest on the taxiway.

Flight recorder analysis

As the flight recorders were retrieved by investigators, it was revealed that both flight recorders had been damaged by the impact forces and post-impact fire. The recorders were later taken to the United Kingdom for further analysis by the Air Accidents Investigation Branch.

The flight data recorder revealed that during Flight 1145's final approach the aircraft had passed the decision altitude of Port Harcourt Airport. The decision altitude is the exact altitude where pilots need to find the runway by visual reference until a certain point where the pilot decides to make a call for a go-around when visual contact with the runway has not been established. Flight 1145 leveled off at an altitude of 204 ft, which was below the minimum decision altitude of 307 ft. The airspeed then decreased to 145 knots and the aircraft kept descending even lower than 204 ft. A few seconds later, there was an increase of speed to 151 knots, indicating that the flight crews had decided to initiate a go-around. As the aircraft had descended well below 204 ft, the crew was unable to recover the aircraft as the altitude was too low. The data then ceased functioning when the aircraft speed was at 160 knots.

The cockpit voice recorder revealed that Captain Adebayo had called for a go-around approximately 16 seconds before the crash. As he called for a go-around, the flight crews added thrust and then tried to retract the gear and the flaps. As the flaps had not been completely retracted and the gears were not in its correct position, the "TOO LOW-GEAR" warning sounded.

According to the correct procedures for a missed approach, the flight crews should have set the take-off thrust, retracted the flaps to 15 degree and retracted the landing gear until a positive rate of climb had been established. The flight crews did try to follow the procedure, however the low altitude of Flight 1145, added by the bad weather condition at the time, prevented the flight crews to conduct a proper missed approach procedure. Flight 1145 was flying slightly above its stall speed and the windshear condition caused the airspeed to decrease. As such, the aircraft didn't climb in a timely manner and ultimately crashed onto the ground.