Officials of the United States Transportation Department announced that they have repealed the authorization for Pakistan International Airlines to conduct charter flights to the United States, citing doubts by the Federal Aviation Administration over the legitimacy of Pakistani pilots' certifications.    

The detail is found in a cancellation by the transportation department to Reuters on Friday of a special permit dated July 1. Pakistan grounded nearly a third of its pilots last month after they learned they may have falsified their certificates.

The move follows the grounding of 262 Pakistani airline pilots over bogus licenses in a decision handed out by the government's Civil Aviation Authority. PIA disclosed late Thursday that it would suspend pilots with fake licenses.

Based on sources, Kuwait Air has grounded at least seven Pakistani pilots and 56 engineers, while Oman Air, Qatar Airways, and Vietnam Airlines have released lists of Pakistani pilots, ground crew, and technical personnel.

The UAE's Emirates airline has also suspended all Pakistani airline flights, preventing them from using the airports for transit and destination flights.

The side effect over the dubious license controversy at Pakistan International Airlines is escalating. The US has now joined the European Union in prohibition the carrier from its airspace.

Pakistan was reportedly notified of the US-imposed restriction by email. The prohibition will take effect for six months and is linked largely to issues surrounding pilot certifications. Also impacted are the special flight licenses that have been previously granted to PIA by the US.

Around early this month, the European Union Air Safety Agency halted PIA's permit to operate in Europe for six months. The authorization controversy is the latest in a wave of scandals for the airline. PIA has been shedding a huge amount of cash in the last 15 years.

Last year, PIA's liabilities were pegged at $3.8 billion. In May, a Pakistani A320 crashed in Karachi, claiming the lives of 97 passengers. Pilot error, the probe result disclosed, was to blame for the incident. The justifiability - or otherwise - of the pilot's certifications remains unverified.

The fatal crash led Pakistan's aviation official on June 24 to admit that 260 of the country's 860 pilots had cheated in their pilot's licensure exams, but were still issued licenses by the Pakistan Civil Aviation Authority. The PCAA has remained mum on the controversy, spurring claims the agency is attempting to lay low and just let the issue die down.

Meanwhile, Pakistan's Geo News disclosed PIA had confirmed the U.S. restriction and said it would address the issue through ongoing remedial steps within the company.