Key takeaways
- The AW101 is a three-engine transport, naval and rescue helicopter in the 15-ton class, created as the British-Italian joint project EH101.
- The fastest way to identify it: three engine intakes on the roof, five blades with paddle tips and a bulky fuselage with sponsons.
- In Europe it is flown by the Royal Navy, the Italian Navy and Air Force, and the air forces of Denmark, Norway and Portugal, among others; Poland uses it for its navy.
- The name Merlin is used in Britain, Denmark and Portugal; in Norway it is called SAR Queen, and in Italy the Air Force calls it HH-101A Caesar.
- There is no operator in Germany – sightings here are rarities, for example at exercises or airshows.
Contents
- 1.What is the AW101?
- 2.The features that are enough to identify it
- 3.AW101 or NH90, H225 or Sea King?
- 4.Variants at a glance
- 5.Operators in Europe: where you meet the Merlin
- 6.The Merlin on the flight tracker
- 7.Spotting with consideration
- 8.Photo tips especially for the AW101
- 9.Common mix-ups and how to rule them out
- 10.Conclusion
Profile
| Manufacturer | Leonardo Helicopters (originally EH Industries, a joint venture of Westland and Agusta) |
|---|---|
| Former designation | EH101 (until 2007) |
| ICAO type designator | EH10 |
| First flight | October 9, 1987 (pre-production aircraft PP1) |
| Final assembly | Yeovil (England) and Vergiate (Italy) |
| Engines | 3 turboshafts: Rolls-Royce Turbomeca RTM322 or General Electric CT7 (new aircraft with CT7-8E) |
| Main rotor | 5 blades, 18.60 m diameter |
| Length (rotors turning) | 22.83 m |
| Height | 6.66 m |
| Max. takeoff weight | 15,600 kg |
| Cabin | 2 pilots, 1 crew member, 25+ troops on crash-resistant seats or up to 16 stretchers |
| Max. cruise speed | 277 km/h (manufacturer figure) |
| Range | up to 1,500 km without reserve (manufacturer figure) |
| Max. endurance | 7 h 40 min (manufacturer figure) |
Identifying features
Is this really the aircraft type in front of you?
- Three engines on top of the fuselage: two side intakes at the front plus a third intake in the middle behind the rotor head
- Five-blade main rotor with conspicuously shaped, paddle-like blade tips
- Very large, tall fuselage – clearly bulkier than the NH90 or AW139
- Retractable landing gear: the main wheels retract into side stubs (sponsons)
- Transport and SAR versions with a rear ramp under the upswept tail boom
- Open tail rotor on the tall vertical stabilizer, with a small horizontal stabilizer beside it
Updated: October 2026 – A gray giant hovering over an aircraft carrier, lowering a sonar into the water. A rescue helicopter setting course for a fishing boat off the Norwegian coast. A green transport letting Royal Marines off over the rear ramp: all of that is the Leonardo AW101, known in many countries as the Merlin. With three turbines and more than 15 tons of takeoff weight, it is one of the largest helicopters regularly flying in Europe. Here you learn how to recognize it with confidence, which versions exist and where you have the best chance of a sighting.
A three-engine helicopter for your hangar
With Planetrack you log every Merlin sighting with photo, type, registration, operator and spot – from the rescue helicopter to the naval submarine hunter. Planetrack is launching soon – join the waitlist and get early access.
What is the AW101?
The AW101 is a medium to heavy multirole helicopter with three engines. Leonardo quotes the maximum takeoff weight at 15,600 kilograms – more than twice that of the AW139. The main rotor measures a good 18.6 meters in diameter, and with its rotors turning the aircraft is almost 23 meters long. According to the manufacturer, the cabin seats more than 25 troops on crash-resistant seats, or alternatively takes up to 16 stretchers. Transport and rescue versions have a rear ramp through which even small off-road vehicles fit.
The roots go back to the late 1970s. Britain needed a new anti-submarine helicopter for its navy, and Italy was looking for a successor to its Sea Kings. Westland and Agusta founded the joint venture EH Industries for the purpose, and the helicopter was accordingly called the EH101. The first pre-production aircraft lifted off in England on October 9, 1987. In 1995, Britain and Italy ordered the first production aircraft.
After Westland and Agusta merged into AgustaWestland, the type was renamed AW101 in 2007, and today it is part of the Leonardo lineup. It is built at two sites: in Yeovil in the southwest of England and in Vergiate in northern Italy. Power comes either from three RTM322 engines from the cooperation of Rolls-Royce and Turbomeca (now Safran) or from three CT7 engines from GE Aerospace. Leonardo now offers new aircraft with the CT7-8E.
Why three engines?
Helicopters with three turbines are rare. On the AW101 the decision was a matter of where it would operate: it was meant to fly long distances over open sea, land on ships and continue safely even after losing a turbine. The third engine adds power reserves when hovering and more safety over water. By the way, Leonardo quotes the maximum range of around 1,500 kilometers for a cruise with only two engines running – a hint of how much power reserve is built into the design. Together with a de-icing system for the rotors, that made the type attractive to operators around the North Atlantic.
The features that are enough to identify it
Among the large helicopters, there are some that look similar at first glance. With the AW101, three observations get you to the answer quickly.
Look at the roof
Behind the cockpit sit two engines with side intakes, followed in the middle by a third air intake directly behind the rotor head. The three engine cowlings on the fuselage spine confirm the three-engine layout.
Look at the blade tips
The five rotor blades end in wide, curved tips reminiscent of paddles. The design comes from a British research program for high-performance rotors and is a very reliable feature.
Check size and landing gear
The fuselage is tall and long, and the main wheels retract into side sponsons. On transport and SAR versions you see the cargo ramp under the upswept tail.
Then there is the tail: an open tail rotor sits on the tall vertical stabilizer, with a small horizontal stabilizer beside it. On naval versions, the rotor blades and tail boom can be folded to save space on board. The Royal Navy’s anti-submarine version also carries a radar fairing under the fuselage. Confirmation comes – as always – from the serial. How to make sense of it on military aircraft is explained in the article Tracking military aircraft online.
Practical tip: count the engines
From below in a flyover, the engines are barely visible. So photograph the aircraft at an angle from the side if you can: then you see the three engine cowlings on the fuselage spine – and have the difference from all twin-engine types right in the frame.
AW101 or NH90, H225 or Sea King?
In Europe the AW101 shares its areas of operation with other large helicopters. A quick comparison helps with identification.
| Feature | AW101 | NH90 | H225 / H215 | Sea King |
|---|---|---|---|---|
| Engines | 3 | 2 | 2 | 2 |
| Main rotor blades | 5, paddle tips | 4 | 5 (H225) or 4 (H215) | 5 |
| Landing gear | retractable gear with sponsons | nose-wheel gear | H225 retractable gear, H215 depends on version | boat hull with floats |
| Rear ramp | on transport/SAR | yes (TTH version) | no | no |
| Impression | very large and tall | compact, rounded nose | slimmer, elongated | angular, boat-like |
The NH90 is the most common lookalike because it takes on the same tasks in many navies and air forces. But it is noticeably smaller and has only two turbines and four blades. The Airbus H225 and its predecessor, the H215 (Super Puma), look slimmer and have no ramp. The Westland Sea King, which the AW101 has replaced with many operators, is instantly recognizable by its boat-shaped hull. The CH-53 is clearly larger and flies with six or seven rotor blades, and the CH-47 Chinook gives itself away with its tandem rotors.
Quick ID: large naval and rescue helicopters
Leonardo AW101 Merlin
Three turbines, paddle tips and a bulky fuselage with sponsons: that is the typical Merlin picture. To be safe, check the serial.
NHIndustries NH90
Twin-engine, four-blade and more compact. The NH90 flies with many European navies and armies, including in Germany.
Westland / Sikorsky Sea King
The Merlin’s predecessor with many operators. Today it is mostly seen in museums and with a few operators.
For an overview of all common rotorcraft, see the guide How to recognize helicopter types.
Variants at a glance
Hardly any helicopter carries so many names. The most important designations for spotters:
- EH101: the original name from the EH Industries era; older aircraft still appear under it in databases.
- Merlin HM1 / HM2: the Royal Navy’s anti-submarine version. The HM2 is the modernized version and can be equipped with the Crowsnest airborne early warning system – recognizable by the large radar pod mounted on the side of the fuselage and swung down in operation.
- Merlin HC3 / HC3A / HC4: transport versions that first flew with the Royal Air Force and then passed to the Royal Navy’s Commando Helicopter Force. The HC4 was converted for naval use, including folding rotors.
- HH-101A Caesar: the Italian Air Force’s version for combat search and rescue; the Italian Navy flies anti-submarine, early warning and transport versions.
- SAR Queen: the Norwegian rescue helicopter, in service since 2020.
- CH-149 Cormorant: the Canadian search and rescue version.
- VH-71 Kestrel: the failed version for the US President, canceled in 2009.
Other operators outside Europe include Japan, where the type is built under license, as well as several countries that use it for government and transport flights. A large order from India for VIP helicopters was annulled in 2014 after a bribery scandal.
Operators in Europe: where you meet the Merlin
In Europe, the AW101 flies exclusively for armed forces and state rescue services. The figures below come from publicly available overviews and describe ordered or delivered aircraft; how many of them are currently airworthy keeps changing.
United Kingdom: The largest European operator. The Royal Navy flies about 30 Merlin HM2s for anti-submarine warfare and airspace surveillance from frigates and aircraft carriers; the squadrons’ home base is Royal Naval Air Station Culdrose in Cornwall. In addition there are about 25 HC4 transports of the Commando Helicopter Force at Yeovilton in Somerset. Right there is the Fleet Air Arm Museum at RNAS Yeovilton – a good starting point for seeing naval helicopters in action. The Merlin is also a frequent guest at the big military airshow in Fairford; tips for that are in the guide to the Royal International Air Tattoo.
Italy: The Italian Navy has received 22 aircraft, the Air Force 15 HH-101A Caesars for combat search and rescue and special operations. The plant in Vergiate is close to Milan Malpensa Airport, so test and ferry flights are possible in the region. For a look at Italian aviation history, there is the museum Volandia, described as a spot under Volandia at Milan Malpensa Airport.
Denmark: The Danish Air Force ordered 14 aircraft, eight for search and rescue and six as transports. The first SAR helicopters began operating from Karup in 2007; today the Merlins cover rescue services around the Danish coasts. If you travel for plane spotting to Copenhagen, with a bit of luck you will see one of the rescue Merlins.
Norway: As the SAR Queen, the AW101 took over rescue duty from the old Sea Kings from 2020, which were retired at the end of 2023. Norway has ordered 16 aircraft. The helicopters are stationed at bases along the long coast and also fly far out over the Norwegian Sea.
Portugal: The Portuguese Air Force bought twelve Merlins for sea rescue, maritime surveillance and fisheries patrol. They stand on permanent alert at three bases: Montijo near Lisbon, Lajes in the Azores and Porto Santo near Madeira. If you are on a Lisbon trip, it is worth a look across the Tagus.
Poland: The Polish Navy has received four AW101s for anti-submarine warfare and combat search and rescue.
| Country | Main role | Chance of a hit for spotters |
|---|---|---|
| United Kingdom | anti-submarine warfare, early warning, naval transport | high, especially in southwest England |
| Italy | navy, combat search and rescue | medium |
| Denmark, Norway | search and rescue | medium on coasts and SAR bases |
| Portugal | sea rescue, maritime surveillance | medium near Montijo, Azores, Madeira |
| Germany | – no operator | very low, only exercises and airshows |
Fleets keep changing
Military inventories change through modernizations, maintenance pauses and losses. The figures here reflect the state of the sources – before a targeted trip, check current information from the armed forces and the local rules.
Put the EH10 on your wish list
Put the AW101 on your wish list in Planetrack and get notified by a sighting alert when a Merlin approaches or lands at your airport. Planetrack is launching soon – join the waitlist.
The Merlin on the flight tracker
Military helicopters are often only partly visible on tracking sites. Rescue flights from Denmark, Norway or Portugal, on the other hand, show up more often because they operate in civilian airspace. Search for the type code EH10 and filter for military or government flights. How that works in practice is shown in the guides Finding helicopters on the flight tracker and Tracking military aircraft online. Keep in mind: not every aircraft transmits a position, and during ongoing operations restraint is called for.
Spotting with consideration
The Merlin often flies where things are serious: in sea rescue cases, exercises or military operations. A few fixed rules apply.
Ready for your Merlin session?
- I stand on public ground and respect restricted areas around military sites.
- I keep my distance from landing sites – the downwash of a 15-ton helicopter is enormous.
- I do not photograph patients or rescue operations from close range.
- I know the photography rules of the country I am in.
- Camera set: the shutter speed matches the rotor blur I want.
What is allowed at air bases is summarized in the article Photographing military airfields: rules. General tips on locations and timing for rotorcraft are collected in the guide Spotting helicopters.
Photo tips especially for the AW101
The big rotor turns comparatively slowly. That is good for you: even moderate shutter speeds blur the blades into a nice disc.
Show the rotor in motion
Start at 1/125 s and work your way down with a clean pan. A frozen rotor makes the Merlin look as if it is about to crash.
Shoot bursts
With long exposure times, not every frame will be sharp. Shoot bursts and sort them out later.
Capture ramp and hoist
The most exciting pictures come at exercises: an open rear ramp, the rescue hoist in action or landings on a ship’s deck.
A profile for identification
An angled side profile shows engines, blade tips, sponsons and serial – everything you need for a clean entry.
The technique is the same as for propeller aircraft; details are in the guide Photographing propellers: the right shutter speed. For airshow days, the article Photographing airshows helps.
Common mix-ups and how to rule them out
It points to the AW101 if …
- you see three engine cowlings on the fuselage spine
- the five rotor blades have wide, curved tips
- the fuselage looks very large and has sponsons or a rear ramp
- the tracking service shows EH10 as the type
Look closer if …
Conclusion
The AW101 Merlin is one of the most impressive helicopters you can see in Europe: three turbines, a huge rotor with paddle tips and a cabin that fits a whole platoon of soldiers. You are most likely to meet it in southwest England, on the coasts of Denmark, Norway and Portugal, or in Italy. In Germany it remains a rarity – all the greater the joy when it does show up at an exercise or airshow. How rare your sighting really is, you can estimate with the article How rare is my sighting?.
In brief
Three engines, five blades with paddle tips, sponsons and often a rear ramp: that is the AW101. Keep your distance during operations, use a longer exposure for a moving rotor and note the serial – then every Merlin sighting becomes a clean entry.
Summary
- In the late 1970s, Britain and Italy began the search for a Sea King replacement; Westland and Agusta founded EH Industries for the purpose. The first flight took place on October 9, 1987.
- After the merger of Westland and Agusta, the EH101 became the AW101 in 2007. It is built in Yeovil and Vergiate.
- Three turbines, de-icing and long range make it a specialist for missions over the North Atlantic, on ships and for long-range rescues.
- The Royal Navy flies the anti-submarine and airborne early warning version Merlin HM2 as well as the transport version Merlin HC4 for the Royal Marines.
- Engine count, blade tips and size are enough to identify it; the registration or military serial reveals operator and variant.
Frequently asked questions
Is the EH101 the same as the AW101?
Yes. The helicopter was developed as the EH101 by EH Industries, a joint venture of Westland and Agusta. After the two companies merged into AgustaWestland, it was renamed AW101 in 2007. Today it runs under the Leonardo brand.
What is the ICAO type designator of the AW101?
In flight plans and databases you find it under EH10 – a leftover of the old name. The code does not distinguish between naval, transport or rescue versions. Many military aircraft also do not transmit full data, so you settle the variant via the military serial.
Why does the AW101 have three engines?
Customers wanted a helicopter that flies far over open sea and can also continue safely after an engine failure. The third turbine adds reserves and range – according to Leonardo, the maximum cruise range is even quoted with only two engines running.
How do I tell the AW101 from the NH90?
The NH90 has two engines and four rotor blades, the AW101 three engines and five blades with curved tips. The AW101 is also clearly larger and taller. From the side, the Merlin’s third air intake behind the rotor head stands out.
Where can I see an AW101 in Europe?
Most likely in Britain around the naval air stations in southwest England, and in Italy, Denmark, Norway and Portugal. There the navy and air force fly it, often on search and rescue duty. There is no operator in Germany; Merlins only show up here during exercises, ferry flights or airshows.
What was the VH-71 Kestrel?
A version of the AW101 that was intended as the new helicopter of the US President. The program was stopped in 2009 because of spiraling costs; the aircraft that had been built later went to Canada as a source of spare parts, where the type flies as the CH-149 Cormorant.
Can I photograph Merlins at military airfields?
From public ground that is common in many countries, but the rules differ considerably. Follow signs and the guards’ instructions, do not enter restricted areas and do not photograph rescue operations from close range.
Collect the Leonardo AW101 Merlin, don’t just see it
Post a photo with registration, type, airport and spot, check off the type in your hangar and get an alert when a registration you are looking for lands. Planetrack is launching soon – join the waitlist and get early access.
Related aircraft types
Leonardo AW139
Five rotor blades, an open tail rotor and wheels that retract into side stubs: according to Leonardo, the AW139 is the best-selling twin in its class and flies for coast guards, police and offshore operators. Here is how to recognize it.
HelicopterLeonardo AW189
Eight-ton class, five rotor blades, room for up to 19 passengers: the AW189 flies rescue missions for coast guards in Britain and Ireland and takes crews to offshore platforms. Here is how to recognize it and tell it from the AW139, H175 and S-92.
HelicopterLeonardo AW169
Five rotor blades, an open tail rotor, wheels instead of skids: the AW169 is Leonardo’s light twin between the AW109 and AW139. Here is how to recognize it in air rescue, police and military service in Europe.
HelicopterNHIndustries NH90
Angular fuselage, four rotor blades, fly-by-wire: the NH90 is the standard European helicopter of the NATO era. With the German Armed Forces it flies as the TTH, Sea Lion and Sea Tiger; elsewhere it was retired early. Here is how to identify it.
HelicopterAirbus Helicopters H225
Eleven tons, five rotor blades, up to 28 troops: the H225 is the youngest Super Puma. First the star of the North Sea, then grounded after the 2016 Turøy accident, today mainly flying as the military Caracal. Here is how to identify it.
HelicopterAirbus Helicopters H215 (AS332 Super Puma / AS532 Cougar)
Four rotor blades, an open tail rotor, retractable wheeled landing gear and a long, angular fuselage: the Super Puma has flown for oil companies, police and air forces since 1978. Today it is called the H215 – here is how to identify it and its variants.
Related airports & manufacturers
Airports, manufacturers, airline groups and alliances – who is behind them and what you should know as a spotter.
Leonardo
Leonardo of Rome is more than a name on a helicopter door: The Italian group builds the AW139 and AW169, jet trainers and transports, holds half of ATR and makes fuselage parts for Boeing and Airbus. Here is how to recognize its traces at the airport.
ManufacturerRolls-Royce
British engine maker with over a hundred years of aviation history: the Trent family powers the A330, A350, A380 and Boeing 787, while the business jet engines come from Dahlewitz near Berlin. For spotters, Rolls-Royce is the question behind the question – which engine is actually hanging under the wing?
ManufacturerSafran
Safran builds no aircraft – and still sits inside a large share of the airliners you see at the fence. The French group supplies the engines for the A320neo and Boeing 737 MAX through CFM International, powers helicopters and the Rafale, and builds landing gear, brakes and cabins. Here you learn how to recognize Safran technology in the field.
ManufacturerGE Aerospace
The US engine maker from Evendale near Cincinnati is behind some of the biggest fans ever hung under a wing: the CF6 for the 747, 767 and MD-11, the GE90 for the Boeing 777, the GEnx for the 787 and 747-8, and the GE9X for the 777X. If you spot widebodies, GE is almost always in your frame.
Where to see the Leonardo AW101 Merlin
Specific vantage points with the runway configuration, light times, coordinates and an honest take on whether the trip is worth it.
Fleet Air Arm Museum at RNAS Yeovilton
Europe’s big collection on naval aviation sits right at an active military airfield: in the museum you climb aboard the first British Concorde and stand on the rebuilt deck of Ark Royal, while outside Wildcats and Merlins fly. Here is how to get a full spotting day out of Yeovilton.
MuseumVolandia at Milan Malpensa Airport
Italy’s big aviation museum stands in the old Caproni factory halls right next to Malpensa’s Terminal 1. Here you collect the DC-3, DC-9 and MD-80, Italian jets from the G.91 to the M-346 – and next door the long-haul and cargo jets take off.
Related guides from the blog
- Identifying helicopter types: telling H135, H145, Bell, NH90 and CH-47 apart
- Helicopter spotting: rescue, police, military – and where to see them reliably
- Finding helicopters on a flight tracker: follow rescue, police and offshore live
- Tracking military aircraft online: what you can see and where it ends
- Photographing military airbases: what spotters can and can’t do at German air bases
- Royal International Air Tattoo in Fairford: the world’s largest military airshow
- Photographing propeller aircraft: choosing shutter speed and panning