Apparently, Bhoja aircraft burst a tyre.

http://www.dawn.com/2012/03/20/air-traf ... areas.html

KARACHI, March 19: A massive dust storm struck many parts of Sindh and Balochistan, particularly the coastal areas, on Monday, bringing down the visibility level to as low as 200 metres and disrupting domestic and international flight operations at various airports in the country’s southern region.

While several billboards, trees and some electric poles in the interior of Sindh toppled, plunging many areas into darkness, no loss of life was reported due to the dust storm that weathermen said was expected to continue till Tuesday noon.

The northwesterly dusty winds began to blow from Iran towards the coastal areas of Balochistan and Sindh due to a low air pressure here, they said.

The civil aviation authorities said none of the airports was closed. “Pilots are being informed about the visibility situation and it is up to them if they want to land or not,” said CAA spokesman Pervez George.

However, thousands of passengers were stranded at Karachi airport as at least half a dozen flights of the national flag carrier and private airlines were not allowed to fly. An international flight did not land here and returned to the Gulf, sources said. Earlier, they said, a Turbat-bound PIA flight coming from Sharjah was diverted to Karachi airport owing to poor visibility in Balochistan. The plane landed safely, they added.

The sources said that the six flights — PK 731, PK 334, PK 241, PK 257, PK 562 and Airblue flight 406 — were not allowed to take off due to poor visibility.

But at least two PIA flights (PK 309 and PK 267) did land.

During the dust storm, a tyre of a plane belonging to a recently launched airline burst upon landing at Karachi airport due to what was described as a malfunctioning of its auto-break system. The plane, carrying 100 passengers, was coming from Lahore.

At that time visibility was 300 metres.

An Emirates Airlines flight, however, after reviewing the situation did not land here and returned.

The sources said that the flights schedule had been disrupted since 5pm on Monday.

When the visibility at Karachi airport became less than 800 metres, which was the limit of landing equipment available at the airport, it should have been closed, the sources said. They explained that lesser visibility was a severe safety hazard for landing and take-off. Yet Karachi airport was not shut down, raising concerns over the air safety, they added.

Also:
http://www.dawn.com/2012/03/20/duststor ... istan.html

QUETTA, March 19: All PIA flights from Karachi, Lahore and Islamabad were cancelled on Monday after a severe duststorm lashed the Quetta valley and other parts of Balochistan.

The storm which had started on Sunday night blew winds at 70 to 80 miles per hour. The minimum temperature in the provincial capital dropped.

The visibility which fell to zero affected vehicular traffic on main roads and highways.

Reports reaching here from eastern and central parts of Balochistan suggested that strong winds uprooted a large number of trees along roads. Met officials told Dawn that the windstorm kicked up dust, obscuring visibility in several areas of the province