The PAVE Cave

The Bureau of Naval Weapons (BuWeps) issued a Request for Proposals for a ship based helicopter able to lift an 8,000 pounds payload over a radius of 100 NM (115 miles) at a speed of 150 knots (172 mph). Its mission was ship-to-shore transport, downed aircraft recovery, personnel transport, and Medical Evacuation.

Sikorsky chosen as a result of technical, production capability, and cost considerations. However, insufficient funds prevented a contract award. Sikorsky negotiated to lower the R&D costs and reduced the number of prototype helicopters to two instead of the original four requested.

Sikorsky awarded a contract to design and develop a mock-up, a static test airframe, and two YCH-53A prototype helicopters for $9,965,635.

The first YCH-53A performs its initial flight at the Sikorsky plant in Stratford, CT.

First flight “Over the Fence”, a half hour flight over Stratford, Shelton, and Milford, by Sikorsky pilots Lloyd (Opie) Blanchard and Robert Decker.

The CH-53A is introduced to the public.

A U.S. Marine Corp CH-53A flew at speeds as high as 170 knots (196 mph) at gross weights of up to 35,000 lbs. making it the free world’s fastest production helicopter.

First five CH-53A helicopters delivered to operational unit Marine Helicopter Squadron HMH-463 and flown to MCAS Santa Ana, CA for the Fleet Introduction Team (FIT).

The CH-53A arrived in Vietnam.

The U.S. Air Force orders the HH-53B for Combat Search and Rescue (CSAR). It added a refueling probe, drop fuel tanks, a rescue hoist, and featured upgraded T64-GE-3 engines.

First flight of the HH-53B.

First HH-53C CSAR helicopter delivered to the US Air Force. It was an improved variant with a smaller 450 gallon fuel tank in exchange for more armor and better communication systems, but lacked a refueling probe.

A CH-53A helicopter flown by Marine Lt.Col. Robert Guay and Sikorsky pilot Byron Graham performed a series of loops and rolls over Long Island Sound, NY. After the flight, the aircraft was retired due to overstress of the airframe and parked at HM-12 in Norfolk, VA. It was used as a maintenance trainer and affectionately known as "Alphie".  Loop and Roll Video

The first CH-53D helicopter is delivered to the U.S. Marine Corps, after requiring more power for heavy lifting in tropical climates. The new variant featured upgraded engines, originally the T64-GE-412 then later the T64-GE-413. It also included an upgraded transmission to support the more powerful engines, and a revised interior to permit a load of 55 troops.

Two Sikorsky CH-53G helicopters delivered to the German Government. Kits were provided for the next 20 CH-53Gs to Germany, which then built 90 helicopters under license by VFW/Fokker in Speyer.

The first S-65C-3 (CH-53D) helicopters of an order for 7 delivered to the Government of Israel. 35 more were delivered under subsequent orders.

Initial flight of the CH-53D. A VIP transport version designated, "VH-53D" with plush accommodations was used by the U.S. Marine Corps for the U.S. presidential flights.

The USAF requested the need for an integrated system on their HH-53s to enable the rescue platform to perform search and rescue under conditions of total darkness and/or adverse weather in all geographical areas, including mountainous terrain, low level altitude, and capable of penetrating hostile territory.

The first Trans-Pacific helicopter flight by two U.S. Air Force HH-53C helicopters. The historic flight was from Eglin AFB, FL to DaNang South Vietnam with several en-route stops. The flight shortened the delivery time to Vietnam by about 75% and demonstrated the long-range capability of helicopters refueled in the air.

The first RH-53D minesweeper delivered to the U.S. Navy for mine sweeping operations. It also included a pair of .50 cal (12.7 mm) Browning machine guns for detonating mines. The Navy received 30 RH-53Ds beginning in 1973.

First flight of the YCH-53E helicopter, a three engine variant.

The HH-53 modification program was signed and incorporated a radar with terrain following/avoidance avionics called "PAVE LOW III".

Sikorsky delivers the last HH-53 to the U.S. Air Force.

The first HH-53 PAVE LOW, tail number 66-14433, flew its first flight. The flight was originally scheduled for June 6th, but ground aborted due to an error in the fuel jettison system.

The original eight HH-53H’s were the very first U.S. Air Force helicopters modified to become the MH-53J PAVE LOW III. All remaining H-53 B, C, and H models were then modified to the MH-53J model standard. The airframes rolled out in the late 70’s and had the same basic radar, but very different avionics. The J-model PAVE LOW solved many H model problems and provided improved avionics. The only external difference between an early J model and the H model PAVE is the IRCM pod on the sponsons. The H-model PAVE LOW had a long tube like device for IRCM capabilities. The Air Force never flew the H model PAVE LOWs in combat.

First flight of production prototype CH-53E.

Two CH-53E production prototype helicopters are delivered to the Naval Air Test Center for testing.

First production CH-53E delivered to U.S. Marine Helicopter Squadron HMH-464, MCAS New River, NC.

Under the PAVE LOW III program, U.S. Air Force NAVAIR 26BFTG called for the “PAVE LOW III” modification to nine MH-53H aircraft between Sep 1978 and Jan 1980 (the remaining 32 HH-53s soon followed) for night and adverse weather operations. Modifications included forward-looking infrared, inertial global positioning system, Doppler navigation systems, terrain-following and terrain-avoidance radar, an on-board computer, and integrated avionics to enable precise navigation to and from target areas.

The first nine HH-53H Pave Lows became operational, and were transferred from the Military Airlift Command (MAC), where they were to have been CSAR assets, to the 1st Special Operations Wing in the aftermath of the Operation EAGLE CLAW disaster.
Two of the HH-53Hs were lost in training accidents in 1984, resulting in two CH-53Cs being converted to the HH-53H standard as replacements.

All HH-53 and CH-53 helicopters in the U.S. Air Force inventory began modification to the MH-53J Pave Low III Enhanced configuration. The modifications, along with incorporation of a Service Life Extension Program (SLEP) were performed by Naval Air Rework Facility (NARF) at NAS Pensacola, FL, or by the Marine Corps aviation depot at MCAS Cherry Point, NC.

The Air Force selected Lockheed Martin Owego for the Interactive Defense Avionics System/Multi-Mission Advanced Tactical Terminal (IDAS/MATT) modification.

MH-53J 66-14433 is the first H-53 in the world with over 10,000 flying hours.

The U.S. Air Force received the first production-modified MH-53J Pave Low III helicopter converted to MH-53M with Interactive Defensive Avionics System/Multi-Mission Advanced Tactical Terminal (IDAS/MATT) from Lockheed Martin Federal Systems. Two prototype IDAS/MATT modified MH-53Js, were already in use by the 20th SOS.

Lockheed Martin and the U.S. Air Force conducted a ceremony at Crestview Aerospace Corporation in Crestview, FL. to mark the delivery of the 25th MH-53M PAVE LOW IV production aircraft. The 25th aircraft is also the 11th aircraft delivered by WR-ALC under the MH-53M IDAS/MATT Contract Production Option V. 12 aircraft had been delivered previously under Production Option IV, and two pre-production kits had been delivered for trial install and kit-proof aircraft prior to that.

The final flight of the last six remaining MH-53Ms flew their last flight in combat before retiring the airframes and being sent to museums and the boneyard.