PAF public information chief Lt. Col. Restituto Padilla said the engine of UH-1H No. 324 had been recovered from the crash site in Gabaldon, Nueva Ecija and flown to Clark Air Base in Pampanga last Sunday.
The inspection of the engine by the PAF crash investigation team, he said, would help determine what caused the helicopter to crash.
The investigators will be assisted by PAF personnel from the 410th Maintenance Wing, which specializes in Hueys.
Last Sunday, the PAF called off retrieval operations for the bodies of three passengers that remain unaccounted for.
But the bodies of the PAF crew that operated the helicopter have already been recovered and identified.
The crew included pilot 1Lt. Reynaldo Gerodias, co-pilot 1Lt. Jason Salazar, and Staff Sgts. Edgar Ramolete and Wilbert Tacata.
Padilla said the 38 Huey I helicopters in the PAF fleet would remain grounded until all have been inspected and taken on test flights.
Recovery operations were also called off last Saturday to make way for a maintenance check on the Huey II being used in the operations.
The Huey II is the lone helicopter of its class in the PAF fleet.
The Hueys are regarded as the workhorse of the Armed Forces of the Philippines (AFP), ferrying troops and supplies in conflict areas and evacuating combat casualties.
The Hueys also play an important part in disaster relief operations, such as those conducted during last year’s deadly floods in Quezon and Aurora. The Huey that killed Punongbayan was one of eight received in January 2002 by the PAF under the Excess Defense Article (EDA) program of the United States.
The craft was damaged after it made a hard landing during a sortie in August 2003 but was returned to service in May 2004 after thorough repairs.
The PAF has 80 Hueys in its fleet, but 40 have been mothballed, PAF sources said. The PAF also has Sikorsky and Bell helicopters.