Hawaii woman heard 2 booms on night Marine choppers crashed

AP ^ | 16 JANUARY 2016 | AUDREY MCAVOY

[Extremely Extreme Extremist]

HALEIWA, Hawaii (AP) -- A retiree who lives across the street from a Hawaii beach said she heard two booms that were loud enough to shake her house on the night two Marine Corps helicopters crashed off the island of Oahu.

"I threw my blanket off, put my slippers on and ran outside thinking it was a car accident," Elaray Navarro said.

The Coast Guard was notified late Thursday of the crash by another civilian who saw the aircraft flying then disappear and a fireball. Someone else reported a flare in the sky, Coast Guard spokesman Lt. Scott Carr said.

[BwanaNdege]

We had a CH-53 lose 13 feet of one rotor blade while flying at 3,000ft AGL. Folks on the ground said “it exploded”.

If a -53 looses a complete blade (33’ long, IIRC) it shifts the CG of the rotating mass 24 inches. This tries to make the rotor mast oscillate about the new CG in a 4 foot diameter circle, three times per second. It is estimated that the airframe experiences a 30G to 50G acceleration, i.e., it “explodes”.

[doorgunner69]

Our pilot was attempting to back down onto the field hospital pad with our lead bird on the deck with rotors turning. he could not see, relying on the crew chief at the ramp for directions.

I "think" (hey, been 47 years) the moment of rotor impact pretty much killed lift and we went down, then the thing tore itself apart. Upper structure tore off completely, shrapnel everywhere according to they guys on the ground unloading wounded from the first helo. Said the thing was vibrating so fast they could not see it.

[T-Bone Texan]

Your short anecdote deserves a thread all to its own!

[humblegunner]

No, he has an enduring hatred and mission.

What mission might that be?

[doorgunner69]

A lot more to that medevac mission that ended with the crash, luckily it does not give me bad flashbacks. Old man’s memories now.

[USMCPOP]

Somewhere I have a small cross-section of a helicopter blade I've had since the 60's. I think it might be from a Huey. But it looked just like this sketch. Brass and aluminum with extremely thin aluminum skin, about the thickness of a heavy business card. There is no filling or honeycomb. Mine is about 6 inches wide.

[xone]

Newer main rotor blades are fiberglass I think, been awhile since I had to screw with learning H-1 systems. I did fly with metal blades. At six inches yours is a tail rotor blade. Main rotors are wider.

[USMCPOP]

Tail rotor. That would explain the small size and very light construction. Thanks.