All about firefighting operations of Sikorsky S-64E/F and CH-54A/B Skycranes
By Babak Taghvaee
The largest helicopter ever operated by the United States Army Aviation and Army National Guard is CH-54 Tarhe, the military model of Sikorsky S-64 Skycrane helicopter. A total of 60 CH-54A Tarhe helicopters (including six pre-production helicopters) and 29 of its more powerful variant, CH-54B, were manufactured and operated by the US Army (USAR) and the Army National Guard (USARNG) until 1993 when their last examples were retired from service. After retirement from service 36 CH-54As and 22 CH-54Bs found use as firefighter and transport helicopters in 16 different helicopter services companies. As of today, 41 of these helicopters are still airworthy in use of four civilian and privately owned helicopter services as well as Italian and Korean Forest Services, for firefighting helicopters among these Erickson Incorporated with 16 of them in its service is a leading operator.
History of the CH-54As
As the USAR was looking for a replacement for its piston-engined CH-37 Mojave heavy transport helicopters after the Korean War, the need for a new heavy lift helicopter was determined. Sikorsky proceeded to meet the need and subsequently designed and developed the S-64. It was specially designed for carrying heavy loads externally. Thanks to its turboshaft engines, it was capable of carrying cargo twice as much as the maximum amount carried by the Mojave. This was achieved with the help of Pratt and Whitney, which modified its JT12 turbojet engines for installation on the S-64 as turboshaft engines.
The S-64 received the military name designation CH-54A Tarhe, and its first prototype, a S-64, ‘N325Y’ (c/n 64-001), logged its first flight on May 9, 1962. The CH-54A could carry a 10-ton payload and was designed to carry its cargoes externally. By means of a hoist, it could pick up or deposit loads without landing.
The S-64 was equipped with a revolutionary Automatic flight control system and altitude hold, which for its time was considered the most advanced of its kind. It was equipped with kneeling landing gear to facilitate easier loading and help during steep slope operations. The Skycrane had a fly-by-wire system back in 1962, a system that by today’s standards is still advanced.
The S-64 was also equipped with a seat and an additional control system for an aft-facing crew who can control pitch, roll, and yaw with 10-percent control authority. The cyclic grip controlled pitch and roll by normal fore, aft, and lateral movement. Yaw inputs were made by twisting the weight and facilitated easier inspection and maintenance operations.
The 478th Flying Crane Company, 44th Air Transportation Battalion, later renamed the 478th Aviation Company (Heavy Helicopter) ‘Cyclones’, received the first six YCH-54As. After completing testing and training, the unit was deployed to Vietnam to support the 1st Cavalry Division, Airmobile. The ‘Cyclones’ transported bulldozers, road graders, armored vehicles, and downed aircraft, ultimately retrieving over 380 aircraft and saving several hundred million dollars worth of equipment.
The initial group of USAR aircrews were chosen from pilots with a minimum of 500 hours of rotary-wing flight time, a current instrument rating, qualifications for flying turbine-engined helicopters, and at least 250 hours as a pilot or instructor pilot (IP) in cargo or utility helicopters. Not all pilots going through initial entry rotary-wing training at that time received this specific training. The USAR was selective about who was trained to fly these new heavy helicopters.
As more CH-54As were constructed and delivered, more of them were involved in the Vietnam War. Some, like ’67-18416′, were used to drop 10,000-pound bombs to clear landing zones (LZs) during the ‘Combat Trap’ program. The CH-54A would drop an M-121 bomb from 6,000 feet to clear helicopter LZs, detonating at about three feet to create a 100-foot diameter landing area.
CH-54Bs, the Improved Sky-Cranes
The CH-54B was a significant upgrade from the previous CH-54A received by the USAR. The USAR received 54 more CH-54As before the production line transitioned to CH-54B. Following the delivery of the final CH-54A, ’66-18413′, the USAR began to receive the more powerful CH-54Bs. These newer models featured an increased maximum gross weight and higher payload capability. While the CH-54A was powered by two 4,500 shp (3,400 kW) Pratt & Whitney JFTD12A-4A turboshafts, the CH-54B was equipped with two 4,800 shp (3,600 kW) JFDT12A-5A turboshafts. These enhanced engines allowed the helicopter to increase its maximum external cargo load capacity from 20,000lb (9,072kg) in older model to 25,000lb (11,340kg) in newer model.
In addition to the more powerful engines, another key improvement of the CH-54B was its smaller twin wheels designed for landing on soft ground. Along with these visible changes, significant upgrades were made to the avionic systems of the helicopter, including components of an improved AN/ASW-29 Automatic Flight Control System (AFCS).
The USAR lost six more CH-54As before transferring the remaining fleet (49) to the USARNG. Also two of the 29 CH-54Bs of the USAR were lost before transfer the remaining 27 to the USARNG in 1979.
While in service with the USARNG, the CH-54A/Bs not only carried out military missions but also served the public. They were used for airlifting historic aircraft and helicopters to museums, antenna towers and telephone poles to marshes and mountains. Additionally, they were used for humanitarian missions, such as participating in a joint Soviet-US Navy Operation named Breakthrough near Point Barrow in 1988. During this operation, a CH-54B, ’70-18488′ named Isabell from the 207th Aviation Company, Alaska ARNG, used a five-ton hammer to break through the ice in an attempt to rescue three grey whales near Point Barrow, Alaska.
During their service with the USARNG, only three CH-54As were lost. This left the USARNG with 46 CH-54As and 27 CH-54Bs when the type was retired from service in 1993. On January 11, 1993, the last three CH-54s in service with the USARNG, all ‘A’ models in use by the 113th Aviation Regiment, Nevada ARNG were retired from service. The day before, one of these helicopters completed the final flight of the Tarhe in the US military service.
The USAR and USARNG retained ten CH-54As and five CH-54Bs for preservation, display, or transfer to various museums, leaving 36 CH-54As and 22 CH-54Bs to be divested. All of these helicopters quickly entered service with various civilian helicopter service companies in the United States. The ‘D’ Model of the Boeing CH-47 Chinook, a tandem-rotor helicopter, replaced the CH-54A/Bs in the service of the USARNG. Despite being smaller in size compared to the CH-54A/Bs, the CH-47Ds could carry slightly heavier cargo thanks to their two sling-points under their fuselage (26,000 lb or 12,000kg).
In the Civilian Market After Retirement
All three prototypes of the S-64 were used for commercial purposes after the end of their tests. ‘N325Y’ (c/n 64-001) was withdrawn from service following an incident on August 19, 1968. The third prototype (c/n 64-003) was turned into the first S-64F, which, together with the second prototype (c/n 64-002), entered service with Erickson Sky-Crane company in 1970. The second one received the ‘N6959R’ registration code and was operated by the company until it crashed due to control loss in Index, Washington on June 27, 1991. As of October 2024, when this article was written, the third prototype was still in use by Erickson, registered as ‘N176AC’ and named ‘Lucille.’
In addition to the first three prototypes used for commercial purposes, three more S-64s, all ‘E’ models, were manufactured (c/n 64-099 to 64-101) in 1975. The first and last of them (c/n 64-099 and 64-101) were sold to Siller Brothers Incorporated in Klamath Falls, Oregon (N4035S and N4037S), while the second (c/n 64-100) was delivered to Evergreen Helicopters and operated as ‘N4036S’ until August 8, 1978, when it crashed due to pilot error, killing one worker on the ground near Buffalo, Minnesota. As of today, the examples delivered to Siller Brothers are still airworthy.
In 1970, the Erickson Sky-Crane company acquired a second S-64E, a former USAR CH-54A, ’68-18432,’ that was withdrawn from service following an incident on January 9, 1970. The Erickson Company continued operating the two S-64Es until 1992 when the USARNG began retiring its CH-54As and CH-54Bs. In that year, Erickson Sky-Crane (also known as Air-Crane) acquired the necessary licenses to perform all sorts of maintenance on the S-64E/Fs, perform modifications, and even rebuild their badly damaged examples.
Between 1992 and 1996, Erickson acquired five CH-54As and 13 CH-54Bs and had them all rebuilt as S-64Es and S-64Fs with numerous modifications and upgrades. The company also used components, systems, and fuselage from two crashed and badly damaged CH-54As of the USAR to build a new S-64F, ‘N189AC,’ known as ‘Gypsy Lady,’ which received c/n 64-1001. Erickson later acquired ten more CH-54As and two more CH-54Bs from other helicopter services companies that had procured them after their retirement from the USARNG service in the early 1990s. They were also converted into S-64E/Fs by Erickson.
Out of the 36 CH-54As retired from the USARNG service in 1992 and 1993, five were in service with the 1160th Aviation Company, Georgia ARNG; eight were in use by Company E, 185th Aviation Brigade, Mississippi ARNG; five were used by the 137th Transportation Company (Heavy Helicopter), Kansas ARNG; three were used by the 1028th Transportation Company, Pennsylvania ARNG; three were used by the 113th Aviation Regiment, Nevada ARNG; two were used by Company H, 104th Aviation Brigade, Pennsylvania ARNG; and one was used by the 117th Air Control Squadron, Georgia ARNG. The units of the remaining five CH-54As are not known to the author.
The USARNG’s CH-54Bs retired from service in 1992 and 1993 were in use by the 207th Aviation Company, Alaska ARNG (three examples); 208th Aviation Company, Connecticut ARNG (11 examples, including examples previously served with the 207th Aviation Company); and 292nd Aviation Company, Alabama ARNG (seven examples).
After their withdrawal from service, some examples of the CH-54As and CH-54Bs were sent to the Aircraft Maintenance And Regeneration Center of the USAF’s 309th Aerospace Maintenance and Regeneration Group at Davis–Monthan AFB to be stored, while others were spread among multiple museums and bases for preservation. Six CH-54As and two CH-54Bs were transferred to the National Museum of Naval Aviation in Pensacola, which were later sold to Erickson (one CH-54A and two CH-54Bs), Heavy Lift Helicopters Incorporated (two CH-54As), and Helicopter Transport LLC (three CH-54As).
In total, 16 companies acquired 36 CH-54As and 22 CH-54Bs after their retirement from the USARNG’s service. Heavy Lift Helicopters Incorporated acquired two CH-54As; Siller Helicopters acquired four CH-54As, including ’67-18423,’ from the Kenosha Military Museum after its closure in 2002; Erickson Air-Crane (now Incorporated) acquired five CH-54As and 13 CH-54Bs; Lenair Corporation acquired four CH-54As; Silver Bay Logging Corporation bought eight CH-54As; Chet Rasberry Incorporated bought three CH-54As; Evergreen Helicopter Incorporated acquired one CH-54A; Aurora Motorsports Incorporated acquired one CH-54A; Scott-Matt Incorporated bought one CH-54A (later sold it to Heavy-Lift Helicopters Inc); Seco Aviation Company acquired a CH-54A (later sold it to Siller Helicopters); in 2005, Ventures Acquisition Co LLC acquired one CH-54A and sold it to Evergreen Helicopters five years later; Blue Bird Helicopters acquired seven CH-54Bs; and Hawkins & Powers Aviation Incorporated acquired two CH-54Bs.
Many of the companies mentioned above sold these helicopters to other companies after several years of storing them or using them. US Leaseco acquired seven CH-54Bs from Blue Bird Helicopters and had them all transferred to Helicopter Transport Service LLC; Columbia Helicopters acquired three CH-54As from Lenair Corporation, Chet Rasberry Inc, and Turbine Ltd; Erickson acquired two CH-54Bs from Hawkins & Powers Aviation Incorporated; and Siller Helicopters acquired two more CH-54As from Seco Aviation Company and Evergreen Helicopters Inc.
24 Years of Successful Operations in Greece
Greece has faced devastating forest fires for decades, exacerbated by global warming in the past two decades. These fires often overwhelm Greece’s fleet of Canadair CL-215s, CL-415s, and PZL M-18B Dromader firefighting aircraft operated by the Hellenic Air Force and two SA332L1 Super Pumas of the Hellenic Fire Department during the summer months. As a result, Greece contracts three different aircraft and helicopter service companies each year to assist in firefighting efforts.
Since 2000, Erickson Incorporated has utilized its S-64E/Fs to combat wildfires across Greece. In recent years, including 2024, the company has deployed six helicopters to Greece for firefighting operations from May to October.
In 2024, Erickson stationed six S-64Es in Greece (N154AC/748, N173AC/747, N176AC/741, N194AC/735, N218AC/734, N243AC, and N247AC/737) at various Hellenic Air Force bases. These helicopters were instrumental in combating the massive wildfires in the Attica region from August 11 to 14, 2024, dropping tens of tons of water over burning forests near Athens. They also participated in firefighting efforts in the Corinth region between Athens and Patras from September 29 to October 5, 2024, where five helicopters completed four sorties per day in Pyrgos and other mountainous areas.
The S-64E/Fs are preferred for firefighting in Greece due to their ability to snorkel both fresh and saltwater. With a 2,600-gallon water tank capacity, these helicopters stand out in their category. While only six were deployed in 2024, this number could increase to nine in years with more intense forest fires. At the end of each fire season, the helicopters have their rotor blades and water tanks disassembled, loaded onto ships, and sent to Australia and other parts of the world by the end of October.
Three Decades After Retiring From the Military Service
Erickson Incorporated, the holder of the licenses for modification and production of Sikorsky S-64E/F helicopters, has become the largest owner and operator of this helicopter in the world. The company sold six S-64Es and one S-64F to the Korean Forest Service (one of them, ‘HL9467’, crashed on May 9, 2013) for use as firefighter helicopters to combat forest fires in the country. These helicopters were maintained and operated by Erickson under leasing contracts and then after their procurement. Under a similar contract, the Italian State Forestry Corps (Corpo forestale dello Stato) acquired eight S-64Fs (all ex-CH-54Bs) from Erickson for firefighting operations, among which three, ‘I-CFAG’, ‘I-CFAH’, and ‘I-CEAD’, have crashed on July 22, 2024, July 6, 2005, and April 26, 2007, respectively, leaving five as of October 2024.
As of October 2024, a total of 41 Sky-Cranes were still airworthy around the world, consisting of 17 S-64Es, 12 S-64Fs, five CH-54As, and seven CH-54Bs. Ten S-64Es and six S-64Fs are in use by Erickson Incorporated; two CH-54As and two S-64Es are in use by Siller Helicopters Incorporated; two CH-54As and seven CH-54Bs are in service with Helicopter Transport Service LLC; a CH-54A is in use by Evergreen Helicopters; the Italian Forest Service operates five S-64Fs, while the Korean Forest Service has five S-64Es and one S-64F. Siller Helicopters Incorporated also has four more CH-54As in storage, with one in external storage and the rest in good condition with the possibility of restoration in the near future.
Erickson Incorporated, with the largest fleet of Sky-Cranes in its service, currently leads operations worldwide. The company not only performs all maintenance on their fleet but also operates its own fleet, as well as the examples in use by the Korean and Italian Forest Services to combat forest fires globally. Since 1992, the company has completed over 4,000 modifications to the S-64 platform, extending their lives beyond what was expected over six decades ago when they entered service with the US Army.
The S-64E/Fs of Erickson have been equipped with one of the most advanced aerial firefighting systems in the world. In 1992, the company created a 2,600-gallon fire suppression system as a bolt-on accessory for the S-64 helicopters, and in 2000, the company designed and built the ‘Sea Snorkel’ system for dynamic filling (scooping) of the fire suppression tank using saltwater obtained from oceans or other water resources. Thanks to these innovations, the company was awarded its first USFS (U.S. Department of Agriculture Forest Service) exclusive-use contract, revolutionizing the aerial firefighting industry two years earlier (in 1998).
As the life of the main rotor blades of the S-64E/Fs neared its end, Erickson began designing and developing a new composite main rotor blade (CMRB) for them. The first prototypes were tested from 2015, and after five years of testing, the Federal Aviation Administration (FAA) approved it for installation on all of the S-64E/Fs of the company. Thanks to the new CMRBs, the S-64E/Fs will remain in service for several more decades, allowing them to outlive any other helicopter ever designed or built by Sikorsky.
The Erickson’s Competitors (Siller and HTS)
Helicopter Transport Service LLC known as HTS, Siller Helicopters and Evergreen Helicopters are other operators of Skycranes in the United States with nine, four and one of these helicopters currently in their operational use. HTS with two CH-54As and seven CH-54Bs currently in its use is the largest one. Similar to Erickson, the HTS is capable of performing all sorts of maintenance on them including overhaul or depot maintenance of the CH-54A/Bs, S-64Es and their JFTD12 engines. Similar to Erickson, its helicopters use 2,600 gallons (9,750 litres) water tanks, however they have different water Snorkel systems. These tanks are refillable in 45 seconds in as little as 18 inches of water. Their computer-controlled delivery system can systematically deploy water or other suppression agents at varying levels of coverage, as certified by the United States Forest Service Interagency Airtanker Board.
As of October 2024, Siller Helicopters, one of the four companies using S-64/CH-54 helicopters in the United States, has two airworthy CH-54As, two S-64Es and three stored CH-54As. Designed by Sikorsky Aircraft for civilian use in 1968, only twelve S-64Es were ever produced, making the aircraft one of the most sought-after helicopters across the heavy-lift industry. Today, only a fraction of the original production run remains in service, with Siller Helicopters operating two S-64Es. The Siller’s S-64Es were purchased from Sikorsky Helicopters brand new and they, similar to the company’s CH-54As are capable of carrying firefighting water buckets or fixed tanks.
Established in 1975, over the last 40 years the company has flown tens of thousands of hours, and today Siller Helicopters has grown to include firefighting, transmission line construction, ski lift construction, power grid expansion, HVAC (Heating, ventilation, and air conditioning) placement, logging, heavy-lift operations, and hydro-seeding across the U.S.. In addition to the CH-54As and S-64Es, Siller Helicopters has a single Sikorsky S-61A Seaking ‘N3173U’, a former US Navy’s SH-3A anti-submarine warfare helicopter (US Navy Bureau Number 149916) equipped with fixed landing gears and also provisions for installation of water tank and firefighting module under its fuselage, and a more modern variant of that, a S-61V-1, ‘N45917’, previously used by the Indonesian Air Force as VIP helicopter between 1965 and 1991.
