Sikorsky CH-53

Sikorsky MH 53 sur Wikipedia.en

The Sikorsky MH-53 Pave Low series is a long-range [Vous devez être inscrit et connecté pour voir ce lien] (CSAR) [Vous devez être inscrit et connecté pour voir ce lien] for the [Vous devez être inscrit et connecté pour voir ce lien].

The series was upgraded from the HH-53B/C, variants of the [Vous devez être inscrit et connecté pour voir ce lien].

The HH-53 "Super Jolly Green Giant" was initially developed to replace the [Vous devez être inscrit et connecté pour voir ce lien].

The helicopters later transitioned to Special Operations missions.

The U.S. Air Force's MH-53J/M fleet was retired in September 2008 and was replaced by the [Vous devez être inscrit et connecté pour voir ce lien].

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Design and development


The US Air Force ordered HH-53B and HH-53C variants for [Vous devez être inscrit et connecté pour voir ce lien] units, and developed the MH-53J Pave Low version for Special Operations missions.

The Pave Low's mission was low-level, long-range, undetected penetration into denied areas, day or night, in adverse weather, for [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and resupply of [Vous devez être inscrit et connecté pour voir ce lien].

Pave Lows often work in conjunction with [Vous devez être inscrit et connecté pour voir ce lien] for navigation, communications and combat support, and with [Vous devez être inscrit et connecté pour voir ce lien] for in-flight refueling.
^{[Vous devez être inscrit et connecté pour voir ce lien][Vous devez être inscrit et connecté pour voir ce lien]}
The large green airframe of the HH-53B earned it the nickname "[Vous devez être inscrit et connecté pour voir ce lien]".

This name is a reference to the smaller [Vous devez être inscrit et connecté pour voir ce lien], a stretched variant of the [Vous devez être inscrit et connecté pour voir ce lien], used in the [Vous devez être inscrit et connecté pour voir ce lien] for combat search-and-rescue (CSAR) operations.

An MH-53 Pave Low helicopter, like the one pictured flying over Florida, crashed near Duke Field at approximately 11:45 p.m. Sept. 7, 2007. The helicopter can fly long ranges at low levels in adverse weather. The Pave Low is from the 20th Special Operations Squadron at Hurlburt Field, Fla.

(U.S. Air Force photo by Senior Airman Andy M. Kin).

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HH-53B

The US Air Force favorably regarded their Sikorsky S-61R/HH-3E "Jolly Green Giant" long-range combat search and rescue (CSAR) helicopters and was interested in the more capable S-65/CH-53A. In 1966, the USAF awarded a contract to Sikorsky for development of a CSAR variant of the CH-53A.

The HH-53B, as it was designated, featured:

• A retractable in-flight refueling probe on the right side of the nose.
  
• Spindle-shaped jettisonable external tanks with a capacity of 650 US gallons (2,461 L), fitted to the [Vous devez être inscrit et connecté pour voir ce lien] and braced by struts attached to the fuselage.
  
• A rescue hoist above the right passenger door, capable of deploying a [Vous devez être inscrit et connecté pour voir ce lien] on 250 feet (76 m) of steel cable.
  
• Armament of three pintle-mounted General Electric [Vous devez être inscrit et connecté pour voir ce lien]/A 7.62 mm (.308 in) six-barreled [Vous devez être inscrit et connecté pour voir ce lien]-type machine guns, with one in a forward hatch on each side of the fuselage and one mounted on the tail ramp, with the gunner secured with a harness.
  
• A total of 1,200 pounds (540 kg) of armor.
  
• A Doppler navigation radar in the forward belly.
  

HH 53B

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Early HH-53Bs featured T64-GE-3 turboshafts with 3,080 shaft horsepower (2,297 kW), but these engines were later upgraded to T64-GE-7 turboshafts with 3,925 shaft horsepower (2,927 kW).

Five crew were standard, including a pilot, copilot, crew chief, and two [Vous devez être inscrit et connecté pour voir ce lien].
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While waiting for delivery of the HH-53Bs, the Air Force obtained two [Vous devez être inscrit et connecté pour voir ce lien] CH-53As for evaluation and training.

The first of eight HH-53Bs performed its initial flight on 15 March 1967, and the type was performing CSAR missions with the USAF Aerospace Rescue & Recovery Service in Southeast Asia by the end of the year.

The Air Force called the HH-53B the "Super Jolly". It was used for CSAR, covert combat operations, and "snagging" reentry capsules from [Vous devez être inscrit et connecté pour voir ce lien]-[Vous devez être inscrit et connecté pour voir ce lien].

A U.S. Air Force Lockheed HC-130P Hercules refueling a Sikorsky HH-53B Super Jolly Green Giant helicopter of the 40th Aerospace Rescue and Recovery Squadron over North Vietnam, some time between July 1969 and July 1970.

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HH-53C

The HH-53B was essentially an interim type, with production quickly moving on to the modestly-improved Air Force HH-53C CSAR variant.

The most visible difference between the HH-53B and HH-53C was that the HH-53C dispensed with the fuel-tank bracing struts.

Experience with the HH-53B showed that the original tank was too big, adversely affecting performance when they were fully fueled, and so a smaller 450 US gal (1,703 L) tank was adopted in its place.

Other changes included more armor and a more comprehensive suite of radios to improve communications with C-130 tankers, attack aircraft supporting CSAR actions, and aircrews awaiting rescue on the ground.

The HH-53C was otherwise much like the HH-53B, with the more powerful T64-GE-7 engines.

A total of 44 HH-53Cs were built, with introduction to service in August 1968.

Late in the war they were fitted with countermeasures pods to deal with heat-seeking missiles.

As with the HH-53B, the HH-53C was also used for covert operations and snagging reentry capsules, as well as snagging reconnaissance drones.

A few were assigned to support the Apollo space program, standing by to recover an [Vous devez être inscrit et connecté pour voir ce lien] in case of a launchpad abort, though such an accident never happened.

In addition to the HH-53Cs, the Air Force obtained 20 CH-53C machines for more general transport work.

The CH-53C was apparently very similar to the HH-53C, even retaining the rescue hoist, the most visible difference being that the CH-53C did not have an in-flight refueling probe.

Since CH-53Cs were used for covert operations, they
were armed and armored like HH-53Cs.

The Super Jollies made headlines in November 1970 in the unsuccessful [Vous devez être inscrit et connecté pour voir ce lien] from the [Vous devez être inscrit et connecté pour voir ce lien] prison camp, as well as in the operation to rescue the crew of the freighter [Vous devez être inscrit et connecté pour voir ce lien] from [Vous devez être inscrit et connecté pour voir ce lien] fighters in May 1975.

The Air Force lost 17 Super Jollies in the conflict, with 14 lost in combat – including one that was shot down by a
North Vietnamese [Vous devez être inscrit et connecté pour voir ce lien] on 28 January 1970 while on a CSAR mission over [Vous devez être inscrit et connecté pour voir ce lien] – and three lost in accidents.^{[Vous devez être inscrit et connecté pour voir ce lien]}

The HH-53B, HH-53C, and CH-53C remained in Air Force service into the late 1980s.

Super Jollies operating in front-line service were painted in various camouflage color schemes, while those in stateside rescue service were painted in a natty overall gray scheme with a yellow tailband.

A good number of Super Jollies were converted into Pave Low special-operations helicopters, the subject of the next section. [Vous devez être inscrit et connecté pour voir ce lien] or Pave is a [Vous devez être inscrit et connecté pour voir ce lien] code name for a number of weapons systems using advanced electronics.

HH/MH-53H

The USAF's Super Jollies were useful helicopters, but they were essentially daylight / fair weather machines, and downed aircrew were often in trouble at night or in bad weather.

A limited night / foul weather sensor system designated "Pave Low I" based on a low-light-level TV (LLLTV) imager was deployed to Southeast Asia in 1969 and combat-evaluated on a Super Jolly, but reliability was not adequate.

In 1975, an HH-53B was fitted with the much improved "Pave Low II" system and re-designated YHH-53H.

This exercise proved much more satisfactory, and so eight HH-53Cs were given a further improved systems fit and redesignated HH-53H Pave Low III, with the YHH-53H also upgraded to this specification.

All were delivered in 1979 and 1980.

The first nine Pave Lows became operational July 1, 1980, and were transferred from the [Vous devez être inscrit et connecté pour voir ce lien], where they were to have been CSAR assets, to the [Vous devez être inscrit et connecté pour voir ce lien] in the aftermath of the [Vous devez être inscrit et connecté pour voir ce lien]
disaster.

Two of the HH-53Hs were lost in training accidents in 1984, and so two CH-53Cs were brought up to HH-53H standard as replacements.

The HH-53H retained the in-flight refueling probe, external fuel tanks, rescue hoist, and three-gun armament of the HH-53C; armament was typically a [Vous devez être inscrit et connecté pour voir ce lien] on each side, and a Browning .50cal (12.7mm) gun in the tail to provide
more reach and a light anti-armor capability.

The improvements featured by the HH-53H included:

• A [Vous devez être inscrit et connecté pour voir ce lien] AN/AAQ-10 forward-looking infrared (FLIR) imager.
  
• A Texas Instruments AN/APQ-158 terrain-following radar (TFR), which was a digitized version of the radar used by the A-7. It was further modified to be able to give terrain avoidance and terrain following commands simultaneously (first aircraft capable of this unique feature).
  
• A Canadian Marconi Doppler-radar navigation system.
  
• A Litton or Honeywell inertial guidance system (INS).
  
• A computerized moving-map display.^{[Vous devez être inscrit et connecté pour voir ce lien]}
  
• A radar-warning receiver (RWR) and chaff-flare dispensers.
  

The FLIR and TFR were mounted on a distinctive "chin" mount.
The HH-53H could be fitted with 27 seats for troops or 14 litters.

The upgrades were performed by the Navy in Pensacola, reflecting the fact that the Navy handled high-level maintenance on Air Force S-65s.

In 1986, the surviving HH-53Hs were given an upgrade under the CONSTANT GREEN program, featuring incremental improvements such as a cockpit with blue-green lighting compatible with [Vous devez être inscrit et connecté pour voir ce lien] (NVGs).

They were then reclassified as "special operations" machines and accordingly given a new designation of MH-53H.