Alert Sign Dear reader, online ads enable us to deliver the journalism you value. Please support us by taking a moment to turn off Adblock on Dawn.com.

Alert Sign Dear reader, please upgrade to the latest version of IE to have a better reading experience

.

Wind shear may have caused the tragedy

April 20, 2012

map-bhoja-air-670
Soon after the accident, the government ordered an inquiry. It will be conducted by aviation regulator – CAA’s Safety Investigation Board. - Photo by Dawn

ISLAMABAD: As the pilots of Bhoja Air Flight B4-213 attempted to land amidst rain and strong winds, the unlucky aircraft might have flown into an unexpected wind shear that possibly smashed it on the ground below.

Soon after the accident, the government ordered an inquiry. It will be conducted by aviation regulator – CAA’s Safety Investigation Board. It would be months before the CAA team comes up with an explanation for the accident.

The probe will look into various aspects -- weather, pilots’ role, the condition of equipment, and handling by air traffic controllers and sabotage. Safety record of the airline, whose operations remained suspended for not fulfilling the required criteria, would certainly come under question.

However, pilots and air accident experts, who helped Dawn analyse the tragedy by putting together the chronology of events, say the crash was fairly consistent with what could have been caused by a wind shear. Unfortunately neither the ageing aircraft nor the ill-equipped airport had wind shear detection systems that could have forewarned the pilots and ground controllers. The result was a catastrophe. Wind shear is a meteorological phenomenon involving fast changing wind patterns, mostly downdrafts, that could cause a landing aircraft to lose speed and altitude. If proven this could be possibly the first case of air crash in Pakistan caused by wind shear.

An official of the Met Department confirmed wind shear in the area surrounding the airport at the time of the crash. The pilots were landing under a strong headwind of 30 knots (about 35 mph) picking up to a maximum of 40 knots (some 46 mph) after getting clearance from air traffic control at the Benazir Bhutto International Airport. Airport Manager Ashfaq Hussain confirmed that the aircraft had been cleared to land and there wasno signal of distress from the pilots till they were last in contact with the traffic controllers.

The plane at the time of the accident was flying at about 1500 to 1800 feet. Witnesses say that then it suddenly started to drop and within seconds plummeted to the ground. As the aircraft was making an approach for landing, it is evident that pilots had reduced engine power by then and once caught in the wind shear they had very little time to increase the speed to come out of it.

The aircraft apparently then stalled and fell to the ground. Air planes while landing particularly become vulnerable to wind shear because the wheels and flaps are down, inducing a drag, and engines are not operating at full throttle, making it difficult to remain airborne. On the ground the Bhoja Air jet broke into four pieces with no major signs of burning.

Waleed Hassan, an aviation enthusiast, talking to this correspondent from the site of the accident, said he hadn’t seen any fire tenders putting out fire or smelt burnt substance.

Yes, some of the recovered engine pieces were blackened. This was consistent with the claims by some witnesses, who said they saw one of the engines on fire before the jet came down. Experts say the pilots after getting caught in wind shear may have tried to get out of it by applying power, but one of the engines in the process may have flamed out, in causing the plane to go into ‘unusual attitude’. A lesser likelihood, the experts said, could be fuel depletion.