MANILA, Philippines ? The embattled director general of the Civil Aviation Authority of the Philippines, Alfonso Cusi, has quit his post amid mounting pressure from the Aquino government and after a public dispute over the reshuffling of senior management posts threatened morale at the agency.

His resignation came at a time when the country was undergoing scrutiny by international aviation bodies that would decide whether to remove the Philippines from US and European blacklists of countries deemed to have unsafe aviation.

"I hereby tender my irrevocable resignation as Director General of the Civil Aviation Authority of the Philippines effective 31 December 2010," Cusi said in a December 20 letter to President Aquino.

"The circumstances of my appointment have been politicized by certain quarters and consequently, have cast doubts on my integrity and management competence," he said.

Cusi, an appointee of the Arroyo administration, was protected by a fixed term of office, but in recent months had come under fire from an unfriendly board of directors and CAAP's mother agency, the Department of Transportation and Communication.

Cusi's term would have ended on 2014. His replacement is expected to be former Air Force Col. Ramon Gutierrez.

The board, chaired by Transportation Secretary Jose ?Ping? De Jesus, had appointed seven key management officials without the approval of Cusi, who argued that the appointment did not go through civil service protocols.

The DOTC said the new appointments were made to comply with the requirements set by the International Civil Aviation Authority in order to allow Philippine carriers to return to European skies, and to add flights to the United States.

On the other hand, Cusi said the appointments undermined the reforms the CAAP had made in the past months, and could jeopardize the chance of the Philippines to be removed from international black lists, especially at a time when the ICAO was supposed to be conducting its safety audits.

ICAO postponed its December audit in what Cusi said was a result of the impending revamp within the CAAP, but the DOTC said this was not the case.

The US Federal Aviation Authority is to conduct its audit in the first quarter of 2011. In 2008, the FAA downgraded the Philippines to ?Category 2? from ?Category 1,? which effectively stopped Philippine Airlines, the only local carrier with flights to the US, from expanding services in that country.

In March the EU placed all Philippine carriers on a black list of airlines barred from flying to Europe after the ICAO raised ?serious safety concerns,? including the lack of qualified professionals in key posts at the CAAP.

The FAA and the EU take guidance from the ICAO.