Offshore transport helicopters
Worker transport and rescue missions are carried out safely and efficiently using long-range heavy-lift helos.
By Owen Davies
Contributing Writer
According to one estimate, some 5800 helicopters are operating in offshore missions globally. More than 68% serve oil and gas platforms, leaving 1800 or so for wind-energy farms and other offshore work.
Helicopters used for offshore energy and search and rescue (SAR) operate in hostile environments, often at low altitude and in poor weather. Predictably, they share a large common core of safety, navigation, and survival equipment. Helos used offshore usually have energy-absorbing structures and seats, and crash-resistant fuel systems.
Many carry crash-protected flight recorders and underwater locator beacons. They all have equipment for flotation and ocean survival in bad weather. Most helicopters working offshore can survive in Sea State 5 or 6. Sea State 5 includes waves up to 13 ft and some spray. At Sea State 6, you get waves up to 20 ft with gale force winds.
Expect oversized doors and push-out or jettisonable windows to simplify escape. Some helicopters carry underwater escape lighting. Add external or sponson-mounted life rafts plus individual life jackets or survival suits for all occupants.
IFR glass cockpits and 4-axis autopilots are common for night and low-visibility operations. So are terrain awareness systems and color weather radar.
SAR helicopters invariably carry a powered rescue hoist, high-intensity search lights, and often electro optical (EO) and infrared (IR) sensors. These are also common on energy-sector helicopters likely to be tasked with SAR and medevac service. Helicopters serving offshore wind farms also carry hoists for lowering personnel to small platforms and wind turbines.
With that, let us survey the aircraft commonly found in offshore missions.
Airbus
In 2024, the world’s largest helicopter manufacturer delivered some 57% of the worldwide civil and parapublic helicopter market – a total of 361 aircraft. All 8 of its civilian helicopters are commonly used for EMS and other public service functions. However, 3 are routinely seen in offshore work. According to Airbus, one was even designed specifically for this market.
A small footprint and excellent hover performance in high winds give the 1/2-pilot/10-pax H145 light twin advantages, particularly for the small decks and tight hoist spots of offshore wind turbines.
Combine a speed of 140 kts, range of 475 nm, and a useful load of 4200 lb, and the H145 is also well adapted for transportation to oil platforms.
Airbus reports that some 60% of helicopters serving offshore wind farms are H145s.
For SAR work, the H145 carries all the usual rescue equipment. Typical configurations can accommodate up to 2 stretchers and 3 medical personnel, or 4 or 5 seated survivors plus a medical crew of 2 or 3.
The H175 is a super-medium workhorse gaining popularity in the offshore marketplace. Typical missions are carrying 16 pax out to roughly 170 nm or 12 pax to 220 nm.
Two factors give it competitive appeal – a lower fuel cost than its heavy competitors and the “Rig’N Fly” mode in the Helionix avionics suite.
Adapted from the H225 Super Puma, it guides the aircraft automatically to the missed-approach/decision point, even in IFR conditions. The landing is still the pilot’s job. For unplanned touchdowns, the H175 is certified to Sea State 6.
Airbus specifies an SAR configuration with 5 crew members, 2 stretchers, and one medical wall. This usually means 2 pilots, a winch operator, a rescue swimmer/crewman, and medical staff, plus space for 2 patients in stretchers.
The H225 Super Puma is a heavy twin designed for offshore work. It offers a useful load of 11,907 lb, a top speed of 175 kts, and a range of 452 nm, thanks to a large fuel capacity and an efficient 5-blade main rotor.
Although capable of carrying up to 24 pax, it is generally configured for 2 pilots plus 19 passengers when transporting oil and gas workers to offshore platforms. For SAR missions, the H225 typically carries 4 medical and rescue personnel, with space for 3 stretchers.
Like the H175, the H225 carries the Rig’N Fly automated approach system that flies the helicopter to the visual decision point at the platform, stabilizing approaches in poor conditions.
The helicopter is fully certified for severe icing, for operations in places like the North Sea, the North Atlantic, and the Arctic.
Airbus reports that, before 2016, around 80% of the Super Puma fleet worked in the offshore oil-and-gas sector. Today, only 20 or so H225s are still serving offshore energy platforms out of a global fleet of about 350.
Bell
This manufacturer recommends 2 of its current civilian aircraft for working energy platforms – the dual-pilot, 13-pax Bell 412 and the forthcoming 2-pilot/16-pax 525 Relentless.
The Subaru Bell 412EPX is the latest upgrade in a lineage that stretches back to 1979. It offers a speed of 122 kts with a range of 357 nm. It carries 5385 lb internally or 6185 lb externally. The optional 4-axis autopilot can guide it to a hover over its destination.
Offshore 412s are generally equipped with a 3- or 4-axis autopilot, coupled approaches, moving-map GPS, and often weather radar and a terrain approach warning system.
Safety features include emergency flotation, life rafts mounted on the skid gear, wire-strike protection, and jettisonable exits.
Typical SAR configurations offer space for 4 to 6 SAR/medical crew when rescuees can walk or 2 crew and up to 2 stretchers. The Japan Coast Guard relies on them for these missions.
Bell designed its new super-medium 525 Relentless with offshore work in mind. Its standard offshore layout is 2 pilots plus 16 pax, but a high-density dual-pilot configuration is available for short-range shuttle work for 19/20 passengers.
A max cruise of 155 to 160 kts and a no-reserve range of approximately 570 nm are marketed specifically for flights to distant offshore platforms and deep-water installations.
A “marinized” standard build carries enhanced corrosion protection for saltwater environments, as well as the usual safety hardware.
Certification of the 525 has been delayed repeatedly by demands for extra testing and a shortage of FAA certification personnel with adequate helicopter experience.
Leonardo
A single-pilot medium twin for up to 15 pax, the AW139 is one of the most widely used helicopters in the global offshore-energy market. Roughly 1 in 4 of the 1300-plus AW139s delivered so far serve offshore energy platforms.
The AW139 typically cruises at around 159 kts, with a max cruise of 165 kts. Its range is around 550 nm without reserves. Auxiliary tanks bring that up to around 650 nm.
It carries up to 6500 lb, split between fuel and payload. Call it up to 2000 lb in pure cargo capacity.
For oil-and-gas work, it is usually fitted with high-density, forward-facing seats for 12 to 15 pax.
The AW139 is also commonly used for personnel transfer, technician shuttles, and logistics to large offshore wind projects, particularly in the North Sea and other deep-water markets. Optional icing protection makes the AW139 all-weather-capable.
For SAR work, cabin layouts often carry extensive medical gear and 2 to 4 rear-cabin crew. A common setup includes 2 or 3 medical attendants and 2 stretchers, with additional seating for 2 to 4 survivors.
Leonardo markets the 1/2+8/10 AW169 light-medium twin as part of the company’s “energy services” family.
Think of it as a slightly miniaturized AW139. It cruises at 140 to 145 kts with a nominal range of 430 to 450 nm with standard fuel and no reserves. Useful load is in the neighborhood of 4200 lb.
For energy services, the AW169 is commonly set up as a passenger shuttle optimized for short- to medium-range trips.
The usual layout has 8 to 10 forward-facing passenger seats. Optional ice protection includes main- and tail-rotor deicing for operation in cold-weather regions.
In SAR configuration, a medical interior provides room for 1 or 2 stretchers, with seating for medical/SAR crew and ambulatory survivors.
For offshore use, the AW189 is a 2+16 super-medium twin. If the AW169 is a scaled-down AW139, the AW189 is the scaled-up version. It cruises at around 150 kts with a range of 400 to 600 nm, depending on fuel and configuration. Useful load is 6500 to 8000 lb, but that includes fuel. Full ice protection system is an option.
Typical SAR configurations have 2 pilots and 3 to 5 cabin crew, and seats for 6 to 10 rescuees. Modular interiors commonly fit 2 or 3 stretchers with full medical equipment and at least 2 medical attendants.
For high-capacity casualty evacuation, the aircraft supports up to 4 stretchers with less workspace and fewer extra seats.
Safety equipment includes a main gearbox designed for 50 minutes operation after an oil loss and optional personal locator beacons, and emergency breathing systems where required.
Robinson
For most offshore missions, Robinson’s R44 and R66 are simply too small and too short-range, and their reliance on single piston engines discourages offshore work. So does VFR-only certification. Yet, they do occasionally appear over the water.
The float-equipped R44 Clipper I and Clipper II cruise around 101 and 102 kts, respectively.
No-reserve range is about 300 nm. Although they are not common, a few companies use them for visits to near-shore oil and gas platforms.
The R66 Turbine Marine is a 5-seat helicopter with pop-out floats. It cruises around 120 kts and offers a maximum range of about 325 nm.
Depending on power settings, it can remain in the air for 3.5 to 4 hours. For offshore work, their utility is about the same as the R44.
Robinson does not market them for oil-and-gas operation but rather for over-water touring, private/utility flights, and general safety for flights where an emergency water landing is a credible risk.
For SAR use, they are limited to ad hoc searches and occasional pickups very close to shore.
Sikorsky
The world’s first helicopter maker is a mainstay of offshore operations. However, since the S-76 was discontinued, only 1 model suited to ocean energy service and SAR remains.
The 1/2+19 S-92 – technically the S-92A, the primary civilian variant – has been the gold standard for offshore operations for the past 20 years. With a high-speed cruise of 151 kts and a long-range cruise of 136 kts, the S-92A has a maximum range of 547 nm – long enough for any mission open to sling wings. Safety features include rotor ice protection and a flotation system certified for Sea State 6.
Despite recent competition from super-medium helicopters such as the Airbus H175 and the Leonardo AW189, the S-92 remains a leading option for SAR and for carrying personnel and cargo to offshore oil rigs, thanks in part to 2 recent enhancements. New last year, the S-92 Phase IV main gearbox includes an auxiliary lubrication system that engages automatically if primary oil pressure is lost.
Sikorsky also offers 1-time extensions of scheduled inspection intervals for specific main gearbox housings.
This puts off more than a year of downtime by 1200 hours and 3600 takeoff-to-landing cycles. For an average offshore operator, that is 12 to 18 months of additional operational life.
The aircraft is also eligible for Sikorsky’s Total Assurance Program, providing power-by-the-hour coverage for over 90% of replacement parts.