North Sea Helicopter Incidents 1964-1993

North Sea Helicopter Incidents 1964-1993

‘I do fly to work by helicopter. It’s a reality.’ – Mike Ashley.

Hopping on and off helicopters to get to and from platforms/vessels is not without hazard. Choppers occasionally have a bad habit of going into the drink or impacting mother earth hard, with fatal outcomes, even though safety and maintenance routines were world-class. It is historically calculated that North Sea helicopter flights were tenfold more dangerous than transatlantic airplane journeys, albeit multifold safer than riding a motorbike on Thai roads.

Back in 1985, I could not even imagine how many designs and models of helicopters I would sit in as a passenger – AgustaWestland AW 109, Westland Sea King, Sikorsky SH-3 Sea King, Sikorsky S-61L & N, Sikorsky S-76A & Mk II, Sikorsky S-92, Aerospitale AS 332L & L1 & L2 Super Puma, Aerospitale AS 332L Tiger, Aerospatiale SA 365 Dauphin 2, MIL MI-8, Bell 212 & 214ST, and a Robinson R-22 that I would fly for a few hours around San Francisco, California, USA, as a student in November 1992, nor could I imagine how many helicopter flights I would take over the following thirty-five years in the North and South Americas, West Africa, Western Australia, Western Europe, Scandinavia, and Asia. In retrospect, after retiring in 2021, I estimate that somewhere between four hundred and fifty to five hundred hours or more were spent in whirly birds offshore, flying to, from, and between installations and vessels.

I would survive a horrendous, fixed-wing plane crash in 2000, but blessedly I did not have the misfortune to experience a helicopter crash. Still, I have, over the years, experienced the impact of severe horrendous weather phenomena that arose during chopper flights in storms, with extreme losses of altitude and being weightless thrown around like a ping pong ball held in place by four-point seat belts, a lightning strike while in flight, an emergency aborted take-off from a rig, engines failing to start, severe, dangerous vibrations during a flight, thrice landing on the wrong installations offshore Western Africa, and a very close call impact with crests of a set of waves.

The most memorable flight lift-offs from production platforms were in 1985 and 1986, with choppers piloted by American ex-Vietnam gung-ho experienced veterans who would hover to the edge of the Statfjord fields and the Gullfaks A platforms helidecks and then drop seemingly straight towards the water, down far below and level out before impact. Being weightless for a couple of seconds, like bungee jumping, was enjoyable. The final remnants of the airborne cowboy era ended a few years later.

Below are listed numerous minor incidents accompanied by several severe accidents with helicopters utilised for flights to, from, at, and between oilfields and associated vessels, installations, and heliports/airports in and around the North and Norwegian Sea basin. Incidents of such a noteworthy degree that officials and aviation accident commissions have conducted independent investigations. To generalise, I have deemed the Northern Norwegian Sea included under the designation North Sea.

There have been numerous midair collision near misses; most such incidents reported by Dutch, Norwegian and UK commercial helicopter pilots active in the offshore oil and gas industry were near-miss experiences with various types of military, primarily fixed-wing aircraft. Helicopters have suffered uncontrolled and unplanned losses of altitude, fires, partial engine failures, primary rotor blade spindle fractures, tail rotor control system failures, bird strikes, lightning strikes, wave water impact while on offshore helidecks, hard landings, tail strikes on runways, decks and guard rails, landing gear failure, icing, wheel brake failures, near collisions with civilian and military aircraft, cracks in fin root structures, loss of oil pressure, loss of fairings, loss of bonding strips, detached cowlings, horizontal stabiliser detachments, incapacitated pilots, a loose pilot seat during landing, snow and ice build-up shutting down engines, incipient vortex ring conditions, loose snagged cargo strop damaging tail fuselage, plastic bin liner into turbin while hovering offshore, inspection hatch released and impacted tail rotor, cabin door released and dropped off during take-off, heli-raft cover separated in flight, tail pylon contacted radar antenna tower on a platform, collision with a parked lorry during taxing at a heliport, communication and navigational equipment failures and numerous deck landings on wrong offshore platforms/rigs/vessels.

Landing on the wrong offshore rig/vessel/platform helideck is a mistake that can easily be made. However, the consequences are significantly more concerning than parking a car in the wrong parking area. Such a mistake, caused by a pilot, instrument, visibility, or air traffic control error, can have dire consequences in a worst-case scenario. There are good reasons to avoid landing on a deck that is not standing by for an arriving aircraft, as there is neither a standby boat, helicopter landing officer (HLO), or fire guards; cranes might be in operation, adding to the collision risk. If the heli deck is on a vessel pitch, roll and heave movements might exceed aircraft limitations, gas could be leaking, the platform or rig could be flaring, loose items could be stored on or around the helideck, maintenance work on or around the helideck might be ongoing, ships alarm, H2S gas drills might be ongoing on/under/in the close vicinity of the heli deck, radio silence procedures may be on force on the installation (e.g. when explosives charges are being prepared), the helideck might not be rated for the aircraft type, and more.

On the other hand, if the deck is open and expecting inbound aircraft, then there is the risk of a second helicopter heading for the right deck! While landing on the wrong deck does increase risk, in practice, with many similar installations often in close proximity to each other, and various human factor challenges, destination misidentifications occur a few times yearly in the North Sea.

Objectively one must be mindful of the sheer number of flights undertaken over the decades, often in appalling conditions. Helicopter operations safety standards in British and Norwegian sectors of the North Sea are acknowledged to be the highest in the world. The North Sea is the world’s busiest global airspace region for offshore-bound helicopters, representing twenty-two percent of international traffic, followed by Brazil with eleven percent, West Africa, and the US Gulf of Mexico with eight percent each; the remaining fifty-one percent shared amongst remaining regions. After the turn of the century, Aberdeen Dyce Airport’s four adjacent heliports have had daily between one hundred and twenty to one hundred and fifty departures/arrivals.

To add further context, hundreds upon hundreds, if not thousands of lives that otherwise could well have been lost to ferocious, inhospitable unforgiving seas in the maritime coastal and offshore areas of the North Sea basin have been saved by helicopter Search and Rescue (SAR) crews over the decades; the sheer number of missions accomplished by these unsung heroes is staggering, literally performing tens of thousands of flights throughout the decades.

The first commercial helicopter flights performed to and from an offshore installation on location offshore in the North Sea, Norwegian sector, were performed on 18 July 1966, the day before the first oil well was spudded in the Norwegian sector of the North Sea. The flights were with a Sikorsky S-61N registration number LN-ORE from Stavanger Forus Airport to and from the MODU Ocean Traveller on hire to Esso, Exploration Norway. This six main + thirteen supports-column, four pontoon Semi-Submersible drilling rig built at Avondale Shipyard in New Orleans, owned by Ocean Drilling & Exploration Company (ODECO), had been wet towed across the Atlantic from New Orleans, Louisiana, USA, to Dusavik Stavanger, Norway. This crossing took fifty-two days during May and June of 1966. The MODU was on anchor about ninety nautical miles directly west of Forus Airport. The pilots were Commander Mike Boxill and test pilot Ed Mullins from Sikorsky as co-pilot; the flight was understandably without passengers. The first flights with passengers were performed to and from MODU Ocean Traveller on 19 July 1966. The pilots were Commander Kjell Bakkeli, and the co-pilot was Michael (Mike) Boxill.

Michael (Mike) Boxill, Kjell Bakkeli, and Jan E. Liderud, accompanied by the technical mechanic Per Listerud, had been in Connecticut for three months, familiarising themselves with the S-61N aircraft type. The aircraft with registration number LN-ORE was owned by Helikopter Service AS and had arrived in Norway on 11 July 1966, having been flown by Helikopter Service pilots from Connecticut via Montreal, Seven Islands, Shefferville, Fort Chimo, Frobisher Bay, Cape Dyer, Søndre Strømfjord, Angmagssalik, Reykjavik, Hofn, the Faroe Islands and Shetland Isles to Stavanger Forus airport, as there were no specialised ships for transporting helicopters of this size at that time.

The second Sikorsky S-61N, purchased by Helikopter Service AS registered as LN-ORH, arrived in Stavanger on 01 August after having been flown over from Connecticut by Jan E. Linderud, touching down at Forus Airport 01 August 1966, where an old decrepit WWII German barracks popularly called Bangladesh was used as the heli base. The company hired one-third of an aircraft hangar (hanger number two). Helikopter Service AS employees used these spartan surroundings as offices, stores and cantine. The WWII barracks were, even in 1966, basically ready for demolition but were in use until 1978 when the company moved into a new terminal/administration and simulator building also at Forus.

Scancopter-Service AS was founded in Oslo on 20 February 1956; on 28 March 1957, the company’s name was changed to K/S Helikopter Service. In 1958, offices and bases were opened at Bergen and Bodø Airports and later in Tromsø. Several difficult years followed the founding as pilot B. Hovden prudently wrote, “Peaky mountains and deep valleys, underpowered and lots of worries,” after several accidents due to “reckless flying and hazardous use of the machines among some pilots.”

The company lost a Bell 47J Ranger LN-ORE on 06 March 1958 and an Agusta-Bell 47J3 Ranger LN-ORH on 02 July 1958; these two aircraft were historically the second and third Norwegian registered civilian helicopters to have crashed. The first Norwegian civilian documented helicopter crash was a Sikorsky S-55 LN-ORK that crashed on 25 February 1954. The fourth loss was a Westland Whirlwind Series I (S-55) LN-ORL that went down on 01 January 1961; the first and fourth aircrafts last were operated by the Whale Hunting Company Globus A/S, a company that had been founded in Larvik, Norway, on 14 January 1925; there was no loss of life in these four first accidents.

In 1959, due to financial difficulties, the closure of Helikopter Service A/S was discussed but not implemented. The company suffered a further loss of a Bell 47G-2 LN-ORB helicopter on 08 October 1965, with the loss of the pilot’s life; this was the sixth civilian Norwegian registered helicopter accident reported. The fifth registered crash occurred during a test flight on 09 February 1965, with a Kjeller PK X-2 experimental helicopter developed by Kjeller Flyfrabrikk (aircraft factory), Norway; the pilot died. The seventh loss was a Bell 47G LN-ORW operated by Bergen Air Transport A/S that crashed on 13 October 1965. The eighth crash and the fourth loss for K/S Helicopter Service was a Bell 47J Ranger LN-ORI that went down on 15 March 1966. The ninth was a Bell 47J LN-ORG operated by K/S Helikopter Service that crashed on 20 March 1968.

Just before Christmas in 1969, Michael (Mike) Boxill, while in flight, reported seeing a gas flare on the MODU Ocean Viking, a flame that ushered in a bonanza and Norway’s second oil boom. By 1980 the Norwegian registered company was acquired by Scandinavian Airlines and Fred Olsen, the shipping magnate. In 1996, the name was changed to Helicopter Services Group, and the company acquired British Bond Helicopters, Australian Lloyd Helicopters & South African Court Helicopters. Canadian CHC Helicopter Corporation purchased the group in 1999, and the company name was changed to CHC Helikopter Service in 2000.

Across the North Sea, Bristow Helicopters Ltd began building its oil and gas credentials before the first oil and gas discovery in the North Sea, tracing its beginnings back to an adventurous and shrewd businessman, Alan Bristow. London-born Bristow, a former Royal Navy pilot, established Bristow Helicopters Ltd on 24 June 1955 after landing a contract with Shell Oil Company to transport crews and materials to rigs in the Persian Gulf as the existing boat service was unreliable. Bristow supplied the pilots for Shell Oil helicopters and managed their operation, ferrying men, tools, spare parts, and groceries. A contract with British Petroleum in 1957 enabled Bristow to purchase two Westland Widgeons helicopters. Later that year, realising that few companies could afford helicopter services, Bristow began looking for work on a global basis and successfully ventured into Iran and Bolivia.

Helicopter transportation soon became the preferred alternative to the slower boat service, and Bristow worked to capitalise on the opportunity. The firm expanded to train Royal Navy helicopter pilots at Redhill, Surrey, in 1961, followed by contracts from India, Australia, and New Zealand. By the end of the 1960s, Bristow had also established a training joint venture in Iran. Bristow entered the North Sea offshore market in the mid-1960s and was ideally positioned to take advantage of the oil boom by commencing operations from Aberdeen in 1967. Bristow was the second helicopter operator to arrive in Aberdeen after British European Airways (BEA) Helicopters Ltd (name changed to British Airways Helicopters in 1974. In 1986, British Airways Helicopters Ltd was divested, bought by Robert Maxwell’s Maxwell Aviation Ltd, and renamed British International Helicopters Ltd.).

Bristow’s Aberdeen expansion truly began in the 1970s with Aberdeen Dyce Airport identified as Bristow’s leading oil and gas support hub. In the summer of 1972, Bristow expanded further and sent a single Sikorsky S-61N to share a hangar in Sumburgh on a three-day-a-week contract for Shell’s Bluewater III and Glomar Drillships. Offshore workers were flown there from Aberdeen by fixed wing, and new accommodations for workers and their families were needed. The operation grew, and during the 1970s, at its peak, thirty Sikorsky S-61N daily flights flew from Sumburgh Airport’s heliport, supported by a round-the-clock maintenance operation. By 1975, Bristow was operating from Aberdeen and Sumburgh Airports with eighteen S-61Ns, a Wessex 60, and a Bell 206 Jet Ranger, along with acquiring ten ex-military piston-engine Sikorsky S-58s, and the company continued to grow.

In the fifty-eight years from the winter of 1964 to the spring of 2023, there were twenty-nine oil and gas exploration and SAR-related helicopter accidents with fatal outcomes in the North Sea basin. Without the thousands of highly dedicated world-class ground crews, maintenance engineers, mechanics, electricians, inspectors, flight tower crews, HLOs, managers, safety course instructors, and experienced professional pilots, the fatal accident statistics would have been significantly higher, if not downright horrendous. However, one of every three offshore oil and gas field workers has had bad helicopter experiences, primarily of insignificant or minor severity.

The Barents Sea and areas further north are being opened for oil and gas exploration, remedial and removal work of existing installations in the North Sea, and the green energy revolution with wind, tidal, and wave-generated power industry is ever-increasing, so the declining hydrocarbon production will presumably not significantly reduce the need for rotorcraft.

The North Sea is many things, but she is neither hospitable nor forgiving, especially if you inadvertently end up submerged in her cold and often fiercely rough waters.

The following, listed chronologically by date, are concise synopsises of oil and gas field exploration-related helicopter incidents and accidents that have taken place in the North Sea basin sectors and the Norwegian Sea from the winter of 1964 through the spring of 2024. The listings include elementary data and salvage diving-related information; they do not include extensive technical details available in the individual elaborately detailed government oversight accident investigation reports. The following list of incidents and accidents do not include Air Force (Army or Naval), Police, Air Ambulances, News Corporations or Private rotorcraft nor near misses that were not deemed reportable. Neither does the list include incidents in the Baltic, Arctic, Barents, and eastern Atlantic seas that surround the North Sea and the Norwegian Sea.

It is entirely possible that although I researched this subject thoroughly, there may have been incidents and accidents that remain unreported.

Reported North Sea helicopter incidents and accidents – 1964-1993

Click on the image thumbnail to the right to read a synopsis of each incident.

(Note: The yellow highlighted text is the aircraft Identification number)

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Aviation accidents don’t just occur during helicopter flights; incidents that affect oil and gas offshore field workers also arise during transportation to and from remote heliports!

On 31 July 1979, a chartered Dan Air fixed-wing aircraft, with registration number G-BEKF, crashed into the sea at the end of the runway while attempting to take off from Sumburgh Airport. The flight was returning Brent oil field workers to Aberdeen Airport with two pilots, one cabin attendant, and forty-four passengers. There were seventeen fatalities; drowning was the primary cause of death.

The Hawker Siddeley HS 748 series one aeroplane manufactured in 1962 had been operated by Aerolineas Argentinas and Argentinian state-owned oil company Yacimientos Petrolíferos Fiscales (YPF). It was one of seven Hawker Siddeley HS 748 series one aircraft, Dan-Air acquired from YPF for oil industry support work in the North Sea in 1977. At the time of the accident, it had flown twenty-nine thousand and seven hours. An investigation concluded that the accident was caused by the locked condition of the aircraft’s elevators, which prevented the plane from rotating into a flying attitude. It was thought that the elevator gust lock (Lever of Death) likely became re-engaged during the pilots’ pre-take-off checks and that it was not noticed until the take-off was so far advanced that a successful abandonment within the overrun area could not be made. The re-engagement of the gust lock was made possible by the condition of the gust lock lever gate plate and gate-stop strip, to which non-standard repairs had been made. The co-pilot was found to have traces of tranquillisers in his system. It is unknown if he was in control, as he had less than one hundred hours on this aircraft type.

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On 07 May 1981, the central radio shack on Frigg field received a message from Rogaland Radio station on the mainland at 17.30 concerning an injured man on a fishing boat. Arne Bråten, Odd Myrvang and Steinar Vestrheim, the crew of the infield Bell 212, prepared for an urgent rescue mission. This aircraft was customarily used for shuttle transport between the Frigg platforms but was also equipped for SAR missions. Frigg nurse Svanhild Rolfsen joined the flight. She had arrived offshore that same day. Upon the radio shack receiving the accident report, she was summoned to the radio shack. Nobody else similarly qualified was keen or volunteered to join the mission; Svanhild immediately accepted the responsibility. The fishing vessel was within a twenty-five-minute flight from Frigg. Weather conditions were challenging, with forty-five-knot winds blowing and high seas. The young nurse attached the harness and was lowered by cable to the fishing boat. Due to the wind and the height of the waves, she was dipped into the sea four or five times before she succeeded in getting aboard the vessel. Her survival suit was far too large. Even thow it was the smallest size available, it had not been designed for a petite woman, and the cold water ran down inside. Svanhild recalls: “The rescue service on land asked us whether we could mobilise a helicopter from Frigg. A young man had lost part of his leg. On the way out to the fishing boat, I kept thinking about what awaited me once we arrived. I wasn’t afraid of what I’d find on the boat, but I naturally wanted to do a good job and therefore concentrated on the job. Just thinking about ships is normally enough to make me seasick, but I managed to focus on the patient and what needed to be done. But I hung over the railings and threw up once the man was safely aboard the helicopter.” The victim on the fishing vessel had had his limb torn off in a winch. His fellow fishermen had rendered first aid, but Svanhild had to change the dressing and administer a painkiller. She then fastened the patient to a stretcher and assisted him in being hauled up into the helicopter before she herself was hoisted back aboard. The aircraft flew directly to Haukeland Hospital, Bergen. By 22.00, the Bell 212 four crew had returned to Frigg.

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I recall a “memorable” helicopter story that occurred in 1988. Having just ended my military service, I immediately returned to my position at PETAS. I was scheduled to depart for a week-long offshore job out from Stavanger, Sola Airport’s heliport; a few days hence, Terje, my colleague, on the other hand, had a two-week offshore trip planned to depart from Flesland Airport’s heliport in Bergen the following day. For Terje, prior commitments meant that flying offshore the following day would be a terrible inconvenience, so we agreed to swap our schedules. Therefore, I flew with the chopper out of Bergen Flesland heliport to the MODU Deep Sea Bergen the following day, feeling content because I would receive a two-week offshore bonus; being my first days without a Naval uniform after being released from the Navy, I was financially broke. My flight out was uneventful, and so was the subsequent return flight a fortnight later.

However, Terje’s flight out to the MODO Vildkat was anything but uneventful. On 15 July 1988, the Aerospatiale AS 332L Super Puma LN-OMC, operated by Helikopter Service (HS) AS with Terje and fifteen other passengers, in addition to the two pilots, departed from Sola Airport’s heliport, Stavanger; they had a different destiny, a date with the sea. The Super Puma helicopter made an auto-rotate controlled emergency landing in the North Sea seventy nautical miles southwest of Stavanger, Sola Airport’s heliport.

Terje vividly recalls a tool pusher in the adjacent seat calmly and nonchalantly reading a newspaper until the water flowed into the aircraft cabin, muttering there was no use in panicking. The emergency landing occurred after losing a leading edge rail on one main rotor’s blades, causing the chopper to ditch with a big splash in the sea. Luckily, the pilot’s skill made it a relatively soft landing. Blessedly, the sea state was relatively calm, with three to four-meter seas accompanied by a prevailing wind speed of thirty knots, enabling the passengers and crew to vacate safely into the life rafts. All eighteen on board survived the emergency landing.

Bobbing on the waves clad in his waterproof survival suit and hanging on to a life raft, Terje wondered if anybody knew they had crashed and would show up to rescue them. It took seemingly an eternity, but eventually, salvation arrived. Passengers and crew were pulled from the water, and life rafts winched up one by one into the rescue helicopter. The SAR helicopter brought the shivering men back to Stavanger.

The inverted but still floating helicopter was salvaged twelve hours later by the M/S Polar Queen chartered from Riber shipping by Stolt Nielsen Seaways. The ship was alongside Stoltenberg, Haugesund, when the call for urgent assistance was received. The vessel was down-crewed, but Jostein Kvaløy, a captain who resided in Haugesund, and a skeleton crew of rapidly assembled local sailors were summoned. The ship’s engines were fired up, and the ropes were released. Most of the crew, including the captain, were unfamiliar with the boat, so apparently, there was some confusion and alarm when departing the quayside as the ship started travelling aft, northward towards the bridge in Haugesund Centrum instead of southward towards open waters. The M/V Polar Queen arrived at the location of the ditched still floating helicopter, and the vessel’s crew managed to hook up slings to the main rotor mast and salvage it before it sank. The aircraft was returned to shore, where the accident commission concluded that the blade had insufficient repair from earlier damage and no documentation for completed maintenance.

The aircraft was refurbished, rebuilt as an all-weather search and rescue craft, re-certified, and operative in 1990. It was in use until 18 March 1996, when it crashed two kilometres from the ice edge while filming a polar bear on the sea ice in the Wijdefjorden, Svalbard, during a SAR training mission, with two pilots, two winch operators, one winchman (SAR operative), a government official familiar with the barren area and an observing third pilot. The planned route was from Svalbard Airport Longyearbyen, a small coal-mining town on Spitsbergen Island, in Norway’s Svalbard archipelago, via Austfjorden – Verle – Wadle – Storøy – Kong Karls land – Longyearbyen.

Two men were injured; one had a substantial leg injury, the other had compression fractures to three neck vertebrae, and the other five were uninjured. The aircraft was condemned but transported to Stavanger Sola Airport’s aircraft museum, where, along with another aircraft of the same model, has been used to build one aircraft now on display at the museum. (This helicopter could be deemed as a lucky bird; it was the same aircraft that performed an emergency-controlled landing on a large Polish merchant vessel’s hatch covers on 01 March 1988).

Turning down the advice from the human resources people that he should see a psychologist and sign up for trauma therapy, it did not take long before Terje was booked for another trip offshore and seated the following day yet again in another transport chopper. Mentally having prepared himself to fly again, he waited for take-off. But the helicopter didn’t take off. The engine wouldn’t start, so the pilot kept trying. Every time the pilot pressed the button for ignition, there was a whirring sound, but not proper turbine engine noise, and combustion didn’t follow.

Despite this glaring problem with the engine, the pilot kept trying. By now, the passengers didn’t want the machine to work and wished to get off. It has been said that there are no atheists in foxholes, but you won’t find many on a malfunctioning helicopter, either. Twenty minutes later, the passengers’ prayers were answered when the pilot finally gave up, and they were all allowed to disembark.

Terje was unquestionably having yet another terrible day. Shocked and stunned and just wanting to go home, now he was asked to board a second chopper. Fortunately, this one did manage to take off and stay in the air.

Meanwhile, back in Bergen, choppers ran back and forth to the oil rigs smoothly and on schedule. I had no idea my friend and colleague had such a monumental, horrible day with my name all over it until I had proposed to swap places with him. Cursing all whirlybirds and with both hands firmly gripping the seat’s armrests, Terje told himself that the next time he ran into me, he would convey what a lucky bastard I was.

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During July 1991, while at work on the air dive deck of the DSV Seaway Harrier after recently surfacing from a week-long saturation dive, my attention was drawn to one of the expensive Ekofisk complex’s more petite interconnected flare stack jackets. A helicopter, I believed to be a Bell 212 or a Bell Iroquois UH-1 B “Huey”, with a hanging load, was hovering above a small distant jacket platform. The burden, attached by a wire hung quite a distance below the aircraft, was a load that the chopper pilots were striving to position at the top of a flare boom extension pipe on the small steel jacket structure. I did not envy the rope access crew or scaffolders on the flare stack at the receiving end of the load.

Watching this type of work is very interesting, and I had trouble taking my eyes off the sight. The weather was excellent, with calm seas and clear skies, but the helicopter struggled to maintain position even in perfect conditions. Its load was pendulating and rotating, and the aircraft seemed slightly unstable. I was impressed by the skill of the pilots and knew, statistically, that flying with a hanging load was one of the most dangerous flights for helicopter pilots. A close friend, Per S Knutsen, had recently finished helicopter flight school in the USA and would land a job with Siller Brothers Inc (Aviation), a company established in 1975, with pilots that specialised in performing demanding construction flying, including firefighting, hydro-seeding, transmission line construction, ski lift construction, power grid expansion, HVAC placement, logging and heavy-lift operations.

A few days after watching the fascinating work of these brave men, I was released from duty and returned to Bergen.

Three weeks later, during a planned temporary platform shutdown, on 10 August, a Bell 212 helicopter with registration LN-OSC operated by Helikopter Service (HS) A/S was working in the afternoon at Ekofisk above the 2/4S (Statpipe). Another pilot crew recently performed similar work at the Ekofisk Edda 2/4C platform. An experienced pilot was dispatched from shore on 08 August to help the team install a fifty-two-kilogram, twelve-metre colour-ring marked, aluminium visual reference tube to a flare tower tip at one hundred and thirty metres.

The visual reference was deemed a necessary safety precaution to assist the pilots in maintaining vertical height and horizontal position when heavier loads would later be air-lifted to and from the four-by-four meter square grating covered work area and lift a new flare burner head into place.

The reference pole was installed simply by flying with both aircraft cabin sliding doors open and handing it over to two scaffolders on the flare tower tip platform. The flare tower structure protruded at a thirty-degree angle over the sea, and construction scaffold workers had erected scaffolding around it at altitude to enable the dismantling, removal and replacement of a flare nozzle defuser head.

The helicopter lift-offs and landings were from the helideck of the four-column, dual pontoon semi-submersible Flotel Safe Lancia anchored adjacent to the platform.

On 09 August, four lifts with scaffolding bundles and an oxygen-acetylene burning gear set were lifted to a four-by-four-metre square grating platform, three meters below the flare tip, and work started cutting the old flare nozzle head.

The pole was then released from brackets and should have been returned to Ekofisk Edda 2/4C as they needed it for similar work, but the rope the scaffolders had used to hook it to the wire carabiner below the helicopter parted or slipped off. The pole dropped into the sea and was lost. That afternoon the most experienced pilot returned to shore.

On 10 August, the Bell 212 was flown by pilots Bjørn Krogstad and Arne Hansen, along with mechanic Rolf Thornes. They were to reinstate an identical reference tube to the one lost the previous day, newly sourced from the Ekofisk 2/4H platform. Initially, difficulties arose when trying to position the pole underslung but rigged horizontally, so they landed back on the semi-submersible flotel Safe Lancia‘s helideck utilised as the work base and rerigged the pole to hang vertically below the helicopter as the pilot flying did not want it protruding horizontally throughout the aircraft’s sliding doors.

Once again, the weather was nice, partly cloudy, with a south-westerly breeze as the chopper lifted its load and flew towards the small flare platform. During the positioning, the pilot did not have a visual reference except to the Ekofisk 2/4 S crane tip that had purposely been raised from its boom rest, prepositioned and elevated to the maximum to aid the pilots; however, the crane tip was offset ten meters below the flare boom tip. During the positioning, the helicopter inadvertently lost altitude, moved astern and angled towards its port side. One of the aircraft’s tail stabilisers impacted a scaffolder and the flare tower; thereafter, its main rotor struck the scaffolding with the twelve-metre-long aluminium pipe still hanging below. The severe vibrations and imbalance that arose caused the tail and tail rotor to impact several other places on the tower structure.

The craft then tore itself to pieces mid-air; debris landed on the Safe Lancia flotel and the 2/4 S platform. The main fuselage crashed into the sea after impacting the Ekofisk 2/4S lifeboat deck, causing damage. The three scaffolders managed to climb down the seventy meters of ladders to the upper levels of Ekofisk 2/4S. A small fire ignited on the Ekofisk 2/4S upper deck corner but was extinguished. One crew member on the Safe Lancia deck suffered a glancing blow from the reference pole but was not injured—a close call.

Rescue operations started immediately; John Seldon was the diving superintendent on the four-column, dual pontoon semi-submersible lifting vessel MSV DSV Semi II, working in the field adjacent to the accident site; the semi-submersible was rapidly repositioned to assist with the rescue mission.

In John’s words, “We were alongside the platform when this accident happened, although I didn’t see the incident. One of the bodies was recovered from the sea, another on the platform’s deck, and the third body was caught up near the top of the tower. Sadly he was there for most of the day while scaffolding was erected to enable the body’s recovery. It was a macabre sight, especially as the Smit Semi II bridge was almost level with him. The ROV was already in the water and quickly located the wreckage.”

Sadly all three crew members were pronounced dead on recovery. One member of the three-person strong installation team on the flare tower was slightly injured; it was a miracle those three exposed men did not suffer more harm. The three autopsies concluded they had died instantly from blunt trauma upon impact with the structures and the water. Almost every bone in their bodies was either broken or shattered. This tragedy was yet another reminder of the dangers involved in all parts of offshore work, even when all parties involved strive for the highest level of safety. Saturation divers from the Smit Semi II recovered the main wreckage from the seabed around the platform’s jacket base close to seventy meters deep.

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It is not only the helicopter pilots and passengers that can be harmed; the helicopter landing officer (HLO) and helicopter deck assistant (HDA) crews on vessels and platforms are also at risk if accidents should happen on their helidecks, especially so on medium-sized ships, as vessels yaw, pitch and roll can be quite significant during marginal weather conditions, as was the case on the helideck of the DSV Mayo on 18 April 1992. Three such fatal instances have been recorded in the North Sea.

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On 18 April 1992, two pilots of a Sikorsky S-76A+ G-BOND, operated by Bond Helicopters Ltd, were provided with a comprehensive flight plan early in the morning. The flight plan included touchdowns on MT Alisa Craig, DSV Mayo, Heather A Platform and the floating production unit FPU Emerald Producer (an eight-column dual pontoon conversion of the MODU Ali Baba Semi-Submersible drilling rig) on anchors at the Emerald oil field, UK sector before flying back to Aberdeen Airport’s heliport. All four destinations were in the East Shetlands Basin about two hundred and twenty to forty nautical miles north-northeast of Aberdeen.

The chopper took off from Aberdeen Airport’s heliport at 08:00 with six passengers en route to the tanker MT Ailsa Craig (ex-MT Ruby III, ex-MT Orpheus Asia), a giant oil tanker with a Length-Over-All (LOA) of three hundred and forty-three point four metres and a breadth of fifty-eight metres with a stern helideck. While at the tanker, four passengers disembarked, and five passengers embarked; the next stop was the diving support vessel, DSV Mayo (ex-DSV Stena Mayo), a twin bell, fifteen-man saturation system, DPII class DSV with an LOA of ninety-one metres and a breadth of eighteen meters with a helideck on the bow. The vessel was lying off Unocal’s Heather Alpha platform. Diving had been suspended as weather was marginal, with heavy seas upwards of six meters and substantial winds gusting to over thirty knots. The DSV had steamed three nautical miles from the platform and was on DP with her bow into the weather; the DSV Mayo’s helideck pitch and roll motion reference unit/high accuracy motion sensor (MRU) figures were close to those which would have made helicopter operations unsafe, indicating four degrees roll and four degrees pitch. Just before 10:00, the pilots started their approach towards DSV Mayo’s helideck.

Several passengers said after the incident; they were worried about the amount of vessel roll when the helicopter approached and landed on DSV Mayo; another said the vessel was rolling and pitching like a corkscrew. The chopper landed and seemed stable. The HLO officer shouted at one awaiting passenger to stay clear of the helideck, then along with his two assistants, proceeded towards the chopper to position the wheel chocks and prepare for the one passenger that was to disembark and one passenger that was to embark on the flight. The incoming passenger was assisted by the HLO and led with his baggage from the helicopter’s port side door (the door farthest from the ship’s bridge) around the nose of the aircraft, staying well clear of the tail rotor to a safe area away from the helideck. The HLO then led the departing crew member around the nose of the chopper to the port side door and helped him embark. This was when it went horribly wrong.

When the HLO returned around the nose of the helicopter back to the starboard side, a massive asymmetrical/freak wave impacted the ship, causing the vessel to roll over to the port side tilting and moving the aircraft. At that moment, the helicopter jumped the ropes backwards, and the rotating blades angled lower in front of the aircraft. The HLO did not stand a chance when a main rotor blade hit and sliced off the top of his skull.

At the Aberdeen Sheriff Court inquiry held in 1993, the HDA stated, ”There was a thud, and I turned around and, just out of the corner of my eye, I saw the HLO’s headset splitting. That was what the noise was. He had his back to us, and when the blades hit him, he spun round and just fell.” The terrified HDA clung to the side of the helicopter, then crawled under the aircraft to get off the helideck.

Personally, having spent hundreds of days stationed as a bridge engineer and shift supervisor in bridge control rooms, I have seen helicopters bounce, tip over slightly, land and abort, and shift position in marginal weather conditions; the pilots are, without a doubt, brave men. Today on a modern vessel, real-time MRU updates are given electronically to the pilots; this has reduced the dangers as they can in real-time discern if the conditions are safe enough to attempt a landing and not have to trust, for example, an officer on duty who is on the crew change list. Once in West Africa, I observed a captain determined to disembark after having been on board for a long trip, adjusting the setting on the MRU to just come under the limitations; this nearly caused a crash on the helideck as the helicopter had to conduct an emergency abort; pretty scary to observe. The captain was severely reprimanded, and his lack of reasoning resulted in all crew changes by helicopter being cancelled for the remainder of the contract in that sector; crew change boats were instead utilised. When a helicopter was parked and shut down on the dive ship’s helidecks for an extended period, the pilots often came down below deck to see the saturation system, chambers, dive, and sat control rooms as it fascinated them, as did helicopters fascinate most saturation divers. Several divers I know had helicopter aviation licences; two owned single-engine helicopters; others had fixed-wing aircraft aviation licences. In retrospect, there are several similarities between helicopter pilots and saturation divers, especially in earlier years; they both had driven personalities, a majority were ex-military (Air Force/Navy), above average intelligence, savoured a demanding albeit dangerous occupation, and were meticulous and careful by nature and meticulously careful by nature.

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On 26 March 1993, a classic example of two heroic pilots’ bravery and line-of-duty dedication was witnessed. In 1993, the Norwegian CHC Helikopter Service was awarded a contract with the Vietnamese state operating company (SFC) for offshore oil and gas field helicopter operations based in Vung Tau, Vietnam. Flights were to be flown for Statoil, BP and Australian BHP. Initially, one AS 332L aircraft was utilised, then SFC bought two AS 332L2s, which Norwegian captains flew, while the Vietnamese gained experience with the aircraft type as first officers.

On 24/25 February 1993, a shallow gas pocket blowout erupted on the ocean floor at one hundred and ninety metres deep, several kilometres from the Transocean six-column dual pontoon MODU Actinia semi-submersible, on anchors drilling for BP at the Lan Tay field in block 06/1. The blowout occurred while the drill string bit was at fifteen hundred metres depth. Helikopter Service pilots Per Tjetland and Sigbjørn Stie rapidly evacuated the rig’s non-essential crew on 25 and 26 March.

Sigbjørn Stie elaborates, “We had just taken off from Actinia at about 16:15-16:20, with a course for an adjacent drilling ship with a couple of the last non-essential rig crew members. The gas blowout was already a fact, having due to subterranean fault lines erupted from the seabed several days earlier with an enormous eruption plume by some estimates reaching thirty meters above mean sea level, clearly visible from kilometres further south. We received a radio message a couple of minutes into the flight that the humongous blowout gas, water, and sediments surface plume had moved towards Actinia and now came up below and slightly to the rig’s side. We were requested to return to pick up the critical crew members that had remained aboard as they had to urgently “abandon the rig”.

“We asked about gas conditions, and of course, the answer was that ‘there was no gas reading on the helideck.’ To ensure ourselves as much as possible, we flew directly into the wind above the derrick with the blowout’s gas plume approximately fifty meters to the left of the helideck. The platform now had a clear sloping list toward the boiling water surface at the eruption point. After a steep approach, we landed with ‘light on wheel and nose wheel’ and immediately got the remainder of the rig’s crew on board. It got quite crowded.

“We lifted off and departed at 16:29 without any problems apart from thoughts about possible ignition of the gas. If the wind had blown the gas directly over the helideck, we would have tried to pick up the crew elsewhere on the rig.”

The gas had diverted from the fault line and had come up along the outside of the twenty-inch casing string. Some days later, the pressure subsided, and the wormhole cratered, ending the blowout; the gas had not at any stage ignited.

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