LAHORE: The entire conversation and the chain of events suggest multiple reasons for the crash of the ill-fated PIA flight PK303.
In the light of Air Traffic Control (ATC)-Cockpit Crew pre-crash conversation, spanning a couple of minutes, it seems the inbound aircraft was seeking permission to land on runway 25L (the 25L is used by airliners traveling from north or from south because it is a better new runway while 25R is used by commercial aircrafts).
From the conversation, it seems the copilot was looking for an access to 25L. It also appears this access was denied by the ATC on the first request, asking the aircraft to turn around. Ironically, it is very hard to find the reason for the denied access, especially when the inbound aircraft had already engaged into the landing mode for making a smooth approach at around 2000 feet. However, the landing gear issue could have been the reason for making the aircraft turnaround which is a an SOP in such a situation.
One reason could be the aircraft had some problem with the landing gear for which it might have been asked to take a turn around — the usual standard operating procedure (SOP) taken by aircrafts with this problem. However, there is no mention of landing gear problem in the recorded conversation between the tower and the aircraft. The copilot on the RT (Radio Transmission) sounded calm while telling the tower it was going for a turn around.
In such a scenario, it takes a lot of effort for the crew to disengage approach and pull up for a turn around. Then, the tower tells the pilot to attain 3500 feet altitude. The pilot complies with the instruction, then comes a warning from the tower that he is moving left from the assigned direction for the second approach. Within a second or so, the crew tells the tower they have lost the engine. Then, the tower tells the cockpit they could use either runway. This call is made when the tower believes the aircraft is in trouble.
After that, there were calls of mayday from the copilot who was on the radio while the captain might have been struggling to control the aircraft which was losing altitude fast moving towards left side of the runway.
The whole conversation and the chain of events suggest multiple reasons for the mishap. There's a big question mark as to why the plane was taking a turnaround. The turnaround is usually made when there's a problem with the landing gear. The footage of the crashing aircraft shows no signs of the aircraft either downing the landing gear or pulling it up. Its belly appeared clean. The only hint about some problem with the landing gear can inferred from the tower asking the pilot if he was going for a belly landing. However, there is not such remark from the pilot in this 222-second audio recording.
Secondly, why the tower did not mention about the problem with the landing gear if it was there! What could be assumed other than that, the aircraft somehow lost the left engine (maybe a bird hit) soon after it was asked to turn around. In that scenario, the pilots must have been struggling to control the direction of the plane with one engine giving thrust, while the other is not functional.
In such a situation, the thrust coming from one engine can change the direction of the plane towards the side where the other engine is not operational to match the thrust for keeping the direction and the lift. The pilots then would be left to manage the loss of the thrust from left side by balancing it with ailerons for keeping the aircraft straight.
With half the power gone, even pulling up the aircraft, besides keeping it balanced is an enormous task at low altitude and speed. This might have forced the pilots not to resort to more power for avoiding further tilting of the aircraft, which ultimately led to a gradual stall and crash. This could be seen from the CCTV footage, the pilots were struggling to keep the nose up.
This probability seems more likely in view of the fact the pilot would have done everything to avoid a crash in a populated area.
The second probability could have been the pilot might have lost both the engines due to bird hit where it couldn't pull up after having forced to turn around. That is, it might have pulled left, stabilized and tried to open up the throttles. At this point in time, both the engines might have failed because of the bird hits, leading to instant power loss, forcing the aircraft to crash. This possibility also could not be ruled out.
There are certain very important grey areas in the whole episode. One, why the pilot was asked to turn around when the tower offered both the runways prior to the Mayday call. Usually, the tower gets that much gracious when the aircraft is in dire straits. Since the pilot only mentioned having lost 'an engine' or 'both the engines' after the turn around — either forced to change the direction because of one engine failure or having done so purposefully — the latter call from the tower of having both runways at 303's disposal seemed strange. Moreover, the footage from different sources doesn't show any smoke trail from any of the two engines, which implies the aircraft might have lost one engine because of some technical reason rather than a bird hit, which usually causes explosion and consequent fire and smoke.
The exact cause of crash will be determined after analyzing the blackbox for it was learnt that sometimes the crew and the tower also use a second channel for conversation especially in such circumstances.
While talking to The News former Air Chief Marshall Kaleem Saadat ruled in both the possibilities, saying it could've been a bird hit which made the aircraft to lose direction and altitude simultaneously. He said during approach a bird hit, impacting both engines could be very fatal. However, he added the possibility of left engine becoming dysfunctional could also create problems for the pilots as the right could make the aircraft change its direction even with 20-30% of power being used for landing. He said the nation should wait for investigations to be completed before hurling all sorts of speculations in the media for the mishap was tragic and warranted a serious approach.
Meanwhile, a retired pilot maintained the aircraft crashed because of the bird hit with both its engines lost. Hashim Gardezi while talking to The News, said Karachi has this chronic problem of vultures flying around, posing a great threat to aircrafts operating from Jinnah International Airport. "The Mayday call is only made in special circumstances. As for one engine failure, the pilots can land the aircraft with not much problem. Only when an aircraft loses both the engines during approach that things get seriously problematic. In my opinion, the aircraft lost both the engines which was evident from the radio transmission taking the rounds."
