Pakistan crash raises questions about air safety
The Islamabad crash that killed 152 people - the biggest disaster in Pakistan's aviation history - has opened a Pandora's box of questions about the local air industry.
The national aircraft carrier, Pakistan International Airlines (PIA), has long been plagued with operational issues.
Its flights were banned by the European Union in 2007 because of concerns over safety.
These centred on an ageing fleet. The problem was highlighted in July 2006, when 45 people died in a crash on take-off in the central city of Multan.
A government investigation blamed the ageing aircraft. But critics maintained that falling standards in Pakistan's booming airline industry were the main cause.
The industry saw the emergence of private airlines in the mid-1990s.
PIA had been the only domestic carrier for most of the country's history. But that changed after the government allowed private airlines to operate.
Until 2000, however, most private airlines found it difficult to compete with the stated-funded PIA, and many folded under economic pressure.
Since then, the industry has boomed because of economic growth and a massive increase in domestic demand.
Private airlines have also started operating routes to Europe, and particulary to the UK, which has a large Pakistani community.Maintenance
But critics say the proliferation of routes and business was not met with matching aviation and safety standards.
They say some companies do not maintain their aircraft as regularly as they should.
Concerns have been raised about Airblue.
An employee of Pakistan's Civil Aviation Authority (CAA) told the BBC that in 2008, one of Airblue's aircraft had been grounded in Manchester in the UK - he said an inspector had noted a serious fault with the aircraft several months earlier, and the problem had not been fixed.
Raheel Ahmed, marketing general manager for Airblue, denied this and told the BBC that all aircraft in service had been listed as airworthy by the CAA.
"I have been working with Airblue for the last five years and no such incident comes to my mind. I should add that the company has the most up-to-date aircraft in Pakistan."
There has been no suggestion of past maintenance or technical problems in connection with the aircraft that crashed in Islamabad.
Junaid Amin, the head of the CAA, said: "No aircraft with maintainance requirements can be allowed to fly by the CAA. We maintain the same international standards as those practiced worldwide."
But former pilots and critics of the industry say the CAA does not always abide by these standards.
"There are several instances when the CAA has been at fault for technical difficulties later developed in the flight," an experienced PIA pilot told the BBC.
"For example, the crash in 2006 was due to the plane being overweight. This was clear at the time it was deemed ready to fly - by the CAA."
CAA investigations are generally never made public. However Aijaz Haroon, a CAA board member and head of PIA, denies that there was anything wrong with the plane.
"The 2006 crash was due to an error on the part of the pilot - he forgot to pull up the landing gear while the plane was taking off."
Mr Haroon also says the investigation reports are sent to the pilot's association and relevant bodies - and that members of the public can access them.Experienced pilot
Plane safety is not the only issue - the physical ability of pilots has also been a cause of concern.
"Pilots are now forced to fly hours much in excess of those deemed as viable," AM Rabbani, secretary general of the Pakistan Association of Airline Pilots (Palpa), says.
"This is primarily because a new regulation implemented by the CAA."
But Mr Aijaz Haroon says the associatiom is trying to politicise the issue.
The PIA, CAA and Palpa have a long history of disputes over work-related issues.
"This is not the time for recriminations," he says. "There is no substance at all in any of their claims."
In addition, industry experts say the traffic-control protocols and navigation aids in Islamabad airport leave much to be desired.
"Why was the plane circling at 1,600ft when the minimum for Islamabad is 3,000ft?" a local aviation told the BBC.
At the moment, the jury remains out on which of these factors played a pivotal role in the disaster.
But what is certain is that a thorough and public investigation is needed to answer questions about the 28 July disaster.