Ah, the old 'pebbles in the intake' trick

The New York Times has an article by Heather Timmons about shenanigans in India:

Anil Ambani, the billionaire chairman of Reliance ADA Group, may have narrowly escaped a fatal accident last week after a technician noticed that someone had tampered with his private helicopter while it was parked at a Mumbai airport. Pebbles and gravel had been placed in an intake to the gearbox, according to the company.
On Tuesday, however, the technician, Bharat Borge, was found dead on railroad tracks in Mumbai. He was carrying a letter that referenced the tampering investigation, according to Mr. Borge’s family and Reliance officials.
Debate raged in India on Wednesday over whether Mr. Borge had committed suicide, had been pushed or was yet another accidental victim of Mumbai’s overcrowded commuter trains, which kill an average of 10 people a day. The Mumbai police were investigating both the tampering and Mr. Borge’s death, but they said Wednesday that he had died of multiple fractures and a brain hemorrhage.
On 23 April, Mr. Borge, who was employed by Air Works, the company that maintains Mr. Ambani’s helicopter, noticed that a cap on the copter’s gearbox was ajar as he was getting it ready for a flight the next day, according to Reliance. The copter is used only by Mr. Ambani, his family, and top company executives. Mr. Ambani uses it at least three times a week to commute from his home in Mumbai to the company’s office there, to avoid the city’s notoriously bad traffic.
When Mr. Borge opened the cap, which is about ten feet off the ground, he saw that there were pebbles and gravel in the neck, and he reported it to a supervisor, Reliance said. The pebbles must have been deliberately placed there, and the act was “clearly an attempt to murder,” R.N. Joshi, a senior pilot with Reliance Transport & Travels, said in a 24 April letter addressed to the chief minister of Maharashtra, the state that includes Mumbai. Reliance Transport & Travels is part of the Reliance ADA Group. “Shortly after taking off, the pebbles would have entered into the gearbox and would have caused midair loss of power,” which could have forced the grounding or crash of the copter, Mr. Joshi said.
Reliance ADA Group said Wednesday that Mr. Ambani was now traveling to work by car.
On Wednesday, the government of Maharashtra ruled out corporate rivalry as a possible motive for the tampering. Jayant Patil, the state’s home minister, said during a televised news conference that the state had “not found any evidence that there is a corporate rivalry between two groups” to cause the incident. Mr. Borge’s family, though, claims foul play was involved. His brother Sambhaji said Wednesday during a television interview with CNN-IBN that Mr. Borge could not have committed suicide. The letter Mr. Borge was carrying, which several relatives had seen, said he had been “facing troubles” in recent days, his brother said, adding that “something fishy” had been going on.