By Roy Ramos

ZAMBOANGA CITY, Philippines

A Philippine Air Force pilot and two crewmen died, while another was injured when a military helicopter crashed during a military exercise Thursday in the northern Philippines province of Rizal.

Lt. Xy-zon Meneses, spokesperson for the Army's 2nd Infantry Division, told GMA News the UH-1D helicopter crashed at around 3.00 p.m. local time (0700GMT).

Meneses did not disclose the names of the victims, saying their families are yet to be informed about the incident.

He said military personnel were conducting air to ground and disaster rescue operation training.

"Their practical exercise for the day was over but the chopper experienced engine problem upon landing," he said.

Air Force spokesman Col. Antonio Francisco said all UH-1D helicopters have been ordered grounded pending an investigation as to what caused the incident.

"That’s part of the standard operating procedure until we finish the investigation, or we find out the cause," he said. "We are conducting thorough inspection of the aircraft."

The ill-fated aircraft was one of the seven refurbished UH-1Ds acquired from Rice Aircraft Services a few years ago as part of the AFP Modernization Program.

The bidding for the aircraft was met with controversy after a disgruntled representative of the company said the bidding was rigged by certain Defense officials who received grease money from Rice.