SOSOLISO, ADC CRASHES CAUSED BY HUMAN ERROR, BAD WEATHER

The air crashes involving Sosoliso Airline’s DC-9-32 aircraft registered 5N BFD in Port Harcourt International Airport, Rivers State, on December 10, 2005, and ADC Airlines’ Boeing 737-2B7 with registration 5N-BFK at TungarMadaki, Abuja, on October 29, 2006, were caused by human error and adverse weather conditions, according to the final reports on the accidents’ investigations by the Accident Investigations Bureau (AIB).

On the Sosoliso aircraft which had 110 persons on board, the report described the flight as uneventful until the final stages when it ran into adverse weather.

“At about 1305 hours, when the aircraft was in contact with the control tower, one would have expected the controller to give the prevailing wind conditions to the pilot but, instead, he only cleared the aircraft to land and to also exercise caution, as the runway’s surface was wet (neither did the pilot request for the wind).”

It added that despite the deteriorating weather conditions, neither the pilot nor the air traffic controller (ATC) requested that Federal Airports Authority of Nigeria (FAAN) which controls the airfield lightening system to turn on the airfield lightings. These oversights resulted in the aircraft missing the approach which resulted in the crash.

The report continued: “The navigational aids were all serviceable and available for use on that day and the aircraft was established on the ILS at 6 miles to touchdown. Shortly after, the aircraft encountered adverse weather conditions (headwind to tailwind). The crew was not aware of the prevailing adverse weather conditions since they were not equipped with actual wind situation.

“AlB is of the view that due to the reducing visibility in thunderstorm, rain and low cloud, the crew could not sight the runway particularly when the airfield lightings were not on. In the process, the crew descended well below the decision altitude before they decided to initiate a ‘go around’.”

The report also indicted FAAN for the exposed concrete drainage culvert located at about 70m to the left of runway 21 edge that portends serious danger to aircraft during landing and take-off.

“The aircraft impacted heavily with the drainage culvert, which resulted into its disintegration and fire outbreak.”
It stated that the aircraft on final approach encountered adverse weather with change in wind speed and direction. Also, there was reduced visibility while the attempt by the crew to abort the landing was unsuccessful.

The report further said “the probable cause of the accident was the crew’s decision to continue the approach beyond the decision altitude without having the runway and/or airport in sight.

“The contributory factors were: The crew’s delayed decision to carry out a missed approach and the application of improper procedure while executing the go-around. The aircraft encountered adverse weather conditions with the ingredients of wind shear activity on approach. The reducing visibility in thunderstorm and rain as at the time the aircraft came in to land was also a contributory factor to the accident. And the fact the airfield lightings were not on may also have impaired the pilot from sighting the runway.

“Another contributory factor was the fact that the aircraft had an impact with the exposed drainage concrete culvert which led to its disintegration and subsequent tire outbreak,” AIB said.

On the ADC crash, AIB blamed the pilot for disobeying the instructions from the ATC over the prevalence of adverse weather when other pilots decided to delay their take-off in the interest of safety.

“There was adverse weather at and around Abuja airport at the time the aircraft departed for Sokoto with 105 persons on board comprising two cockpit crew, three cabin crew and 100 passengers. Soon after the aircraft was airborne, several warning signals/sounds of “wind shear” were recorded by the cockpit voice recorder (CVR).”

The report stated that the accident occurred because of “the pilot’s decision to take-off in known adverse weather conditions and failure to execute the proper wind shear recovery procedure resulted in operating the aircraft outside the safe flight regime, causing it to stall very close to the ground from which recovery was not possible.”

Source: Leadership