When did the last helicopter flight out of Vietnam?

At 7:53 AM, April 30th, 1975 the last helicopter took its wings, carrying Major Kean and 10 Marine Security Guards. This helicopter landed on USS Okinawa at 8:30 AM. And it was truly the last helicopter out of Saigon. At 8:54 AM, Operation Frequent Wind concluded.

Does a helicopter need to be grounded?

Helicopters in normal weather will build up a static charge, just ask any ground crew for a logging helicopter. Normally the hook will be grounded by dropping it on the ground before the hooker will touch it. Or a grounding rod will be used to neutralize the static charge.

When necessary for a wheeled helicopter to taxi on the surface?

When necessary for a wheeled helicopter to taxi on the surface, use the phraseology in paragraph 3-7-2, Taxi and Ground Movement Operations. Ground taxiing uses less fuel than hover‐taxiing and minimizes air turbulence.

What clearances do you need to avoid when operating a helicopter?

Avoid clearances which require small aircraft or helicopters to taxi in close proximity to taxiing or hover‐taxi helicopters. AC 90-23, Aircraft Wake Turbulence, Para 10 and Para 11. Issue takeoff clearances from movement areas other than active runways or in diverse directions from active runways, with additional instructions as necessary.

Why do helicopters suddenly lift off the ground?

Helicopters with articulating rotors (usually designs with three or more main rotor blades) are subject to “ground resonance” and may, on rare occasions, suddenly lift off the ground to avoid severe damage or destruction.

When to request a helicopter to proceed expeditiously from one place to another?

When requested or necessary for a helicopter to proceed expeditiously from one point to another, normally below 100 feet AGL and at airspeeds above 20 knots, use the following phraseology, supplemented as appropriate with the phraseology in paragraph 3-7-2, Taxi and Ground Movement Operations.