Saturday, April 21, 2012

Aviation Update

The tragic crash of Bhoja Air flight 213 is in the news, a Boeing 737-200 that went down on approach to Benazir Bhutto International in Islamabad, Pakistan on Friday.  As usual with air disasters there is already plenty of speculation as to cause, right now weather being the most probable.

According to and other sources there were indeed thunderstorms in the area with lighting, hail and gusty winds.  Landing short of the runway on approach is the classic "wind shear" event, something our US aviation system has spent a lot of time and money trying to prevent.  One of the leading experts in discovering these shears was none other than researcher Ted Fujita, whose claim to fame is the "F scale" for measuring tornado damage. 

But as usual there are conflicting reports.  Here's the London Telegraph with a early blurb supposedly coming from official sources in Pakistan:
Air traffic controllers at Islamabad's Benazir Bhutto international airport said the Bhoja Airlines plane was properly positioned when it begun its approach. Then, suddenly, it sharply descended, falling to 200 feet while still travelling at 300 miles an hour, three minutes before it was scheduled to land. The pilot issued a mayday call, saying a fuel tank had caught fire and the plane was out of control. He asked for help to attempt an emergency landing, telling controllers he could see the roofs of homes but not the airport's landing strip. But the airliner descended 50 feet more before its tanks exploded, said a report by Pakistan's civil aviation authority.
Subsequent to this leak the officials have had a news conference during which they reported no mechanical failure.  Not sure how anyone would know at this early juncture but it sounds as if somebody's not keeping track of the narrative too well.

For instance, the 'fuel tank on fire' explanation initially leaked based on 'a report' could rule out wind shear, although it would depend on what the pilot thought was on fire.  If the engine didn't flame out (due to hail ingestion or a firewalling of the power) a fire on board could certainly explain the sudden drop and why they had gone 'out of control'.  Then again if the plane was actually out of control it's unlikely the crew would have been asking for help on the radios in performing an emergency landing.  Indeed the early leak seems to be overcome by events at the latest news conference:
Mr Yousafzai said he had listened to recordings of conversations between air traffic controllers at Islamabad’s Benazir Bhutto international Airport the pilot, Noor Ullah Afridi. All had seemed normal, with the air traffic controller reminding the pilots to lower the plane’s landing gear in preparation for landing. “Suddenly, the blip disappeared from the radar screen and contact was lost with the plane,” Mr Yousafzai said.
In other words, no mention of a fire or a mayday or requests to make an emergency landing. Such changing narratives might be easy to dismiss had they not come from official sources. Or maybe that's exactly why it should be dismissed.  The idea of the fuel tank being on fire would suggest only two likely ignition sources--a lightning strike (very rare) or a man-caused disaster from a bomb or missile. Both could be considered 'acts of Allah', taking liability away from men and throwing it up to the heavens or to shadowy terrorists. Allowing the aircraft to make an approach with a microburst occurring on final approach might tend to put the liability elsewhere depending on their legal system.

But everything is still speculation.  A few things could help explain this better for the benefit of victims' families and aviation safety officials. One, they have the cockpit voice recorder and the flight data recorder, which can confirm or deny the mayday call and indicate whether a catastrophic event occurred before touchdown.   Pakistan's Civil Aviation Authority says they are giving the data to Boeing for an investigation.  Presumably this means the NTSB will be involved but that wasn't stipulated.

Two, most modern jet aircraft in the US fleet now have onboard wind shear detection equipment so they can 'see' these shears on approach and peel off to try again later.  Did this older 737?   If so did the pilots heed the warning?    

Three, was there anyone on the passenger manifest of importance?  Bhoja Airlines released the list very early on, so chances are it was unremarkable as to VIPs.

And four, they need a detailed review of the weather conditions at the exact time of the crash.  Just saying 'there was bad weather' is not good enough--they need to pinpoint the heavy cells, lightning, and hail as finely as possible, assuming they have the technology to interrogate and record such things.  Early reports had the crash near the Chaklala military base in Rawalpindi (where KSM was captured), which is co-located with the Benazir Bhutto commercial airport:

The apparent crash site in "Hussein abad" would be consistent with a wind shear crash.   But it's along the final approach course so it could also be consistent with mechanical failure, a fire or explosion on board, or pilot error.

Finally, there's apparently a third world corruption problem to consider.  Investigators will have their hands full.

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