Esquadra 751: Pride of the Portuguese Air Force

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Our friends at FlyHighAeromedia went to Portugal to witness the operations of one of the most important search and rescue units in the world.
A Mk516 Merlin during a hoist training with the rescue swimmer of the Cliffs near Praia do Areia do Mastro - Björn van der Flier
Base Aérea nº6 is headquartered in the municipality of Montijo, next to the Tagus River and close to the city of Lisbon. Dedicated to the duties of air logistics, dignitaries, maritime surveillance, and search and rescue, it is one of the main bases of the Portuguese Air Force and is home to Squadrons 501, 502, 504 and 751, flying C-130H, C-295M, Falcon 50 and EH-101 aircraft and helicopter types. Another resident of Montijo is the Portuguese Navy with the Lynx Mk95, which are normally fulfill their mission aboard the Navy's frigates. Since its creation in the 1950s, Montijo Air Base has focused its mission on the use of air and naval assets, as a spearhead for maritime operations and is fundamental to support military bases and civil defenses in the remote archipelagos of the Azores and Madeira.
EH101 Merlin Mk514 during a fly-by at Montijo Air Base - Roelof-Jan Gort
The history of the Esquadra 751

To better understand the history of the Esquadra 751, we spoke to Colonel Diniz who has been in the Portuguese Air Force for about 33 years and has been the Commander at Montijo Air Base for about two years, but he has been assigned to Montijo Air Base (with other tasks in his career) for about 13 years. The origin of the squadron takes you back to the wars in Africa that Portugal took part in between 1961 and 1974. At the end of the ‘60s there was a need for a large support helicopter for troop transport, large assault and infantry. That is why the Portuguese Air Force decided to buy twelve Puma helicopters. The Portuguese Air Force, or Força Aérea Portuguesa (FAP) used these in the war from 1969 until 1974. When the war ended there was a political revolution in Portugal, and the nation became a fully fledged democracy again. All their military units and assets from Africa were moved back to the mainland. In 1978, there was a whole reconfiguration of the Air Force.

The Puma helicopters were sent to the Esquadra 751 and 752 (Esq751/752) and their main mission was search and rescue. They were also used for tactical troop transport.

Colonel Diniz continued to tell us the story of how they started the process of selecting candidates to replace the Puma Helicopters. Diniz recalls it was a very long process because it had several setbacks. The first example was delivered in February 2005. These were exciting times for the squadron; they received their first Merlin, then a new example following every few months until they received all twelve they had ordered.

In 2005, the squadron began transitioning to the new helicopters. Colonel Dinez continued that there were two big reasons to replace the Puma helicopters with the EH101 Merlin helicopters. The first reason is that the Pumas were getting old. They were originally built in 1969-1970, with the most recent ones being from 1970. They had been largely modified over the course of years; in 1978 and 1979 external fuel tanks were added, and in 1991 and 1993 the Pumas were equipped with more powerful engines, but they still had the original transmissions. They were very powerful, but due to the original transmissions and rotor blades, their power could not be fully utilized. As the helicopters were quite old, so too were many of their parts, and it became expensive to try to fix everything that would inevitably need to be fixed. Most other countries used newer, more capable helicopters, while Portugal had been left behind, using the Pumas. So, the need was for a more powerful machine, with better overall performance, and that was the main reason to get the Merlin helicopter. The Portuguese Air Force tried to obtain a helicopter that could cover the massive search and rescue area it had been assigned. This is about 5.5 million square km of the Atlantic. The Merlin can technically only go out as far as 400 miles and back (usually only 360), but it was as good as they could get. To cover the area they were assigned, they needed a helicopter that could go out 1200 miles, but nothing was available. Some of the other competitors were the Super Puma, Sikorski S92 and at one point the Blackhawk also joined the competition, but none of these could achieve the same range as the Merlin.
EH101 Merlin Mk516 during a hoist training of the Cliffs near Praia do Areia do Mastro - Roelof-Jan Gort
Different Variants

The helicopters were acquired in three variants, the Mk514, the Mk515, and the Mk516 . The first variant is mainly used for SAR missions; there are about six of these. The second variant comes with additional equipment and is used for fishery control and surveillance. There are two of these. The last four helicopters, Mk516s, are used for tactical missions.


We asked Colonel Dinez if he was satisfied with the Merlin helicopter. He answered that the Merlin is a fantastic machine. The Merlin helicopter is well-engineered in that, if something goes wrong, it most likely will still continue flying. It is great at dealing with malfunctions; you will need a lot to fail before the helicopter will go down. However, mechanically and on a more practical level, the commander’s impression is that the Merlin is not a very reliable machine. They have not yet lost a helicopter due to technical failure, but it does require a lot of maintenance hours to keep it running smoothly. The Canadians and the Danish also have many issues with it, though the British and the Italians are able to come up with solutions to many of the problems, because they are very close to the manufacturing and engineering side. There is a very long repair time wait for both repairable, and new components.
Two system operators are looking to the rescue swimmer during a hoist training at Montijo Air Base - Roelof-Jan Gort

Three crews with their respective helicopters are on alert for 24 hours, and have reaction times of 30 minutes during the day and usually 45 minutes at night. If an aircraft declares an in-flight emergency, the alert can be reduced to 15, 10 or 5 minutes. The Lisbon Rescue Coordination Center, linked to the Air Force Command, is the body responsible for activating an SAR mission from Montijo. The RCC contacts the Air Base Operations section and reports the situation, which could range from a coastal cliff rescue to a complex long-range Search and Rescue mission. A start time of thirty minutes is required for a team meeting and mission planning. If the objective is at a great distance, the determined warning time will have to be slightly extended due to the risk of reconfiguration and/or refueling.

The call comes from the RCC (Rescue Coordination Center) which will activate the procedure and coordination. When Esq751 receives the call, first thing needed is the basic information of the mission, where is it, what is it and factors that can affect the mission.

Every time a distress call is declared at a distance greater than 120 miles from the base, a C-295M aircraft of Squadron 502 is activated simultaneously. This information and exact coordinates are sent to the helicopter, as well as direction, wind speed at various altitude levels and weather conditions in the rescue area, aiding in the EH-101's mission planning, reducing fuel consumption and increasing aircraft efficiency, while decreasing the time to arrival and stay in the operations area. If necessary, the plane can also launch lifeboats to help the castaways while awaiting the arrival of rescue.

Asking about the fixed wing aircraft for the SAR missions, he continued, “After a certain distance from our home base or shoreline we always request SAR support from fixed wing aircraft. This is the C295M from the 502 Squadron, and it is very handy in many ways. The C295M has more endurance and more speed than the Merlin, so they will reach the target sooner. The C295Ms will find the target, they will lock the target for us (the vessel or the person to be recovered). They also relay communications for us, because when we travel this distance, we lose communication with the ATC.”

In the future, Portuguese Air Force KC-390s will be used in search missions, reducing the time of arrival to the operations area by half. When employed, the fixed-wing aircraft is the last to leave the site, and in the event of an accident with the rescue aircraft, it is up to the aircraft to plot the position and keep flying in a circle until another rescue helicopter arrives.
Pilot in command preparing the helicopter for departure - Roelof-Jan Gort
Merlin pilot

FHA has also spoken with Major Daniel Silva, a 36-year-old Pilot who joined the Portuguese Air Force in 2003 and started to fly the Merlin in 2010. To become part of 751 Squadron, you have to accumulate a minimum of about 100 flight hours on a helicopter.

For SAR there is a core crew. There is a captain, co-pilot, system operator (winch operator), rescue swimmer and the flight nurse. Those five people are the core of the rescue operation, but sometimes the crew can add extra people, such as a medical team.

Regarding the challenges for a pilot on a nighttime rescue mission, Major Silva mentioned that nighttime rescue is not easy at all. “Flying at night comes with a lot of rules, you are flying low, you fly in bad weather conditions most of the time and a vessel under you that is moving around. It needs a lot of training, focus, and a lot of trust. So, the need is always to work as a team to be able to perform these missions. Besides this, depending on the size of the vessel, some of them are visible, then you get your references, and you can perform. There were a lot of missions where it wasn’t the case, and the vessel was difficult to find because it was so tiny. In those cases it takes time, and it can feel like a year to bring the Merlin into the right position. In those times the pilot needs to trust the winch operator and rescue swimmer (he’s on the cable and must trust the winch operator). So, trust is the keyword in SAR operations, and it needs to become a part of you as Esq 751 pilot.

Major Silva recalled a particular mission that took place when he was a young pilot with the squadron. When asked to take the crew duty for only two or three hours, he complied. Then, he had to respond to an emergency. It was a really terrible day, winds gusting to 50 kts and heavy showers. A lone sailor was 110 nm off shore and his vessel was sinking rapidly. He was in the water near a rescue dinghy. The sailor, a 78 year old man, died just as the rescue swimmer had been lowered into the water. While flying the body to Porto, there were several problems with electrical generators, presumably caused by the severe rain. “You remember more the ones you’ve lost that the ones you have saved,” said Major Silva.
A full crew poses in front of one of the squadron’s helicopters, from left to right: nurse, pilot, rescue swimmer, pilot, system operator - Björn van der Flier
EH101 Merlin on the platform during a beautiful sunrise - Roelof-Jan Gort