1977 — Oct 21, USMC Sikorsky helicopter crash with troops, Mindoro, Philippines – 24

–24 AP. “24 Now Known Dead in Helicopter Crash.” The Register, Orange Co., CA. 10-22-1977, A2.
–24 Gero, David. Military Aviation Disasters: Significant losses since 1908. 1999, p. 125.
–24 National Museum of the Marine Corps. 10-22-2013.

Narrative Information

Gero:
Date: 21 October 1977 (c.10:30)
Location: Mindoro, the Philippines
Operator: US Marine Corps
Aircraft type: Sikorsky CH-53D (157139)

“The turbine-engine helicopter, carrying a load of troops and also lifting with an external sling an empty water container, or ‘bull’, crashed and burned in mountainous terrain 80 miles (130km) south-west of Manila. Killed in the accident were 24 of the 37 American servicemen aboard the aircraft, including the entire crew of four, while the 13 surviving passengers and a US Navy corpsman who came to the scene to help suffered injuries.

“After it began to life the water trailer off the ground, the rotorcraft yawed to the right, whereupon the crew released the container. At that point, the CH-53 appeared to stabilize momentarily, but then continued wi6th increasing speed in its clock-wise rotation, while in a nose-high attitude. During this time, a number of occupants were ejected from the rear cargo door. Still spinning, the aircraft descended until it struck the terrain 300ft (100m) below the saddle from which it had picked up the water trailer, the impact shearing off its tail rotor and a large portion of the tail assembly. It finally nosed down and slammed to earth, rolling over at least twice before coming to rest generally up-right.

“….It was the opinion of the officer in charge of the investigation that the high gross weight of the aircraft and the density altitude conditions in which it had been operating, requiring high power while both hovering and lifting an external load, exceeded the authority of the tail rotor to counter the torque effect of the main rotor and thus maintain directionally-controlled flight. The external load was jettisoned in an unsuccessful attempt to regain control, and it appeared that the crew then lowered the collective pitch, reducing the power applied to the rotor system, and further tried to fly down the slope of the hill in order to effect recovery, without success. There was no evidence of any mechanical failure factoring in the accident.

“The investigating officer further express the opinion that with proper restraint, all of those killed except the two pilots would have survived the crash, and a number of serious injuries would have been prevented. Though highly experience, the flight crew was considered negligent in trying to lift a load under the prevailing conditions, and the crew chief for not requiring the passengers to use the seat belts that were available; the pilots apparently also failed to supervise him in this respect. With regard to the latter factor, one of the recommendations made in the accident report was that Marine personnel wear helmets and use seat belts when riding as passengers aboard rotary-wing aircraft.” (Gero. Military Aviation Disasters: Significant losses since 1908. 1999, p. 125.)

National Museum of the Marine Corps: “On 21 October 1977, a CH-53 crashed in Mindoro, Philippines during sling load operations due to a design flaw in the tail rotor drive; 31 US Marines serving in Operation Fortress Lightning were killed.” [A list of the victims is contained.]
(National Museum of the Marine Corps. 10-22-2013.)

Newspaper

Oct 22: “Manila, The Philippines (AP) – Rescue workers hacked through jungle to reach the wreckage of a U.S. Marine helicopter today and pulled out 14 more bodies, the Navy said. The new discoveries brought to 24 the number of dead from the crash on a central Philippines island. The Navy said 14 injured servicemen were being treated at U.S. military hospitals on the main island of Luzon. One was a Navy medical corpsman hurt during the rescue operation.

“The CH53-D Sea Stallion helicopter, carrying a crew of four and 33 passengers, crashed Friday in the mountains of Mindoro island, about 80 miles southwest of Manila, as the Navy and Marine Corps ended a two-week training exercise described as the largest amphibious operation in the Pacific since World War II.” (AP. “24 Now Known Dead in Helicopter Crash.” The Register, Orange County, CA. 10-22-1977, A2.)

Sources

Associated Press. “24 Now Known Dead in Helicopter Crash.” The Register, Orange County, CA. 10-22-1977, A2. Accessed 3-12-2020 at: https://newspaperarchive.com/orange-county-register-oct-22-1977-p-2/

Gero, David. Military Aviation Disasters: Significant losses since 1908. The UK: Patrick Stephens Limited, 1999.

National Museum of the Marine Corps. 10-22-2013. Accessed 3-12-2020 at: https://www.facebook.com/USMCMuseum/posts/on-21-october-1977-a-ch-53-crashed-in-mindoro-philippines-during-sling-load-oper/10151794259227880/