Crash of the VNAF Chinook Carrying Montagnard Dependents from Ben Het
The Border Ranger camp at Ben Het came under attack early in the Battle for Kontum. US Army Chinooks were enlisted to fly out as many Montagnard dependents as possible, after delivering loads of ammunition and provisions to the camp. US (John Paul Vann’s) efforts to get VNAF to devote its own Chinooks to the effort were successful after the first few days. When the first VNAF Chinook came to the Kontum landing strip with refugees aboard, I was there, as a (civilian) CORDS Province Development Officer. Thankfully most of the Montagnards had gone down the ramp when something odd happened--the Chinook started bouncing up and down, harder and harder. The pilot or crew chief closed the ramp and at the same the aircraft lifted off, but unsteadily.
It reached about 250 feet, stopped its ascent, then started nodding in place, fore and aft. Soon after that, it began to spin horizontally, still in place and still nodding as it revolved. The rate of spin increased, and several Montagnards still inside were thrown by centrifugal force against the raised ramp, and over it, falling to their deaths.
The pilot managed to slow then almost stop the spin but not the nodding. Then the nose went down and did not come back up, the aircraft tilted to the right, and fell out of the sky, at least partially still under power. It was headed toward the group of CORDS military advisers I was with, and we took off running and looking back at the same time. It fell well short of us—but it fell on a VNAF Huey that had just touched down, also loaded with refugees from Ben Het.
It was inconceivable that anyone could have survived on either aircraft, so the natural thought was not to go near the crash site because there might be an explosion.
But one of us did the right thing, a heroic thing under the circumstances. The mess sergeant, an overweight Guamanian whose name I cannot remember, ran to the crash, disappeared in the smoke and fire for a few seconds, and came running back hell-for-leather. He was holding a small living child by one arm.
In later conversations with chopper pilots, I learned that what happened to the Chinook is called ‘ground resonance,’ the setting up of resonating pressure waves between chopper blades and the ground. But in this case, the bouncing must have damaged something on the chopper’s controls, so that even when the pilot got clear of the ground, the aircraft was unmanageable, and the results tragic.
Rob Schwab <firstname.lastname@example.org>
Thursday, November 01, 2012 at 11:19:10 (EDT)