Overweight Oil Workers Put Strain on North Sea Helicopters

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All helicopters need to operate within specified weight limits. Image by Neil Harrison

In the last two weeks, the media in the UK has been full of reports about North Sea oil workers being put on slimming diets because their average weight over the last few years had increased so much. In 2005, the Civil Aviation Authority increased the weight allocation for each helicopter passenger from 196 lbs to 216lbs. Then recently, Innovative Health Solutions (IHS) director Louise Martin stated that the average weight of an offshore worker had increased by more than 42 lbs in 10 years. But why is this a problem? Does it matter if a large helicopter flies with a few heavier people? And why is it being considered as a safety issue?

Does the Weight of a Helicopter Matter?

Every helicopter, from the very large ones ferrying offshore workers to the oil rigs right down to two-seater training helicopters, has to be careful not to exceed its Maximum All Up Weight (MAUW). This is the maximum weight at which the helicopter is allowed to fly, and includes the weight of the helicopter itself, plus passengers, pilot, fuel etc. In addition, there are issues if the Centre of Gravity (CG), or balance, is outside normal limits. There may also be specific weight limits for different types of performance, such as flying at altitude. If any of these limits are exceeded, it is definitely unsafe for the helicopter to fly.

What Happens if Weight Limits are Exceeded?

Flying at above the MAUW puts a strain on various helicopter components. This may show up immediately and could be minor, but it could cause catastrophic failure at a later date. There is no way of knowing in advance which of these is likely to happen.

Flying with the CG outside of limits is slightly different. It may cause similar effects to flying outside of the MAUW, but it can also have other consequences, including loss of control for the pilot! I have had this happen in a small way, when flying a small airplane with a friend. Being both rather short, we were using lots of cushions in order to reach the rudder pedals, and since we were both sitting very far forward, we had inadvertently put the helicopter’s centre of gravity too far forward. We found this when we tried to land, and had great difficulty in preventing the nose of the aircraft from dropping! It was not a major issue for us, but the addition of extra weight could certainly have tipped the balance in favor of a crash.

North Sea Helicopter Specifications

These are the specifications for the Eurocopter EC225 Super Puma, a commonly-used North Sea Helicopter. Hopefully, they will put the scale of this aircraft into perspective.

Capacity: The helicopter can hold 19 passengers and 1 cabin attendant.

Size: This helicopter is 19.5 m (64 ft 0 in) long, and 4.97 m (16 ft 4 in) high.

Weight: Empty, the helicopter weighs 5,256 kg (11,587 lb) with a gross weight of 11,000 kg (24,251 lb) – the maximum takeoff weight is 11,200 kg (24,692 lb).

Powerplant: This helicopter is powered by two turboshaft engines, which are 1,776 kW (2,382 hp) each.

Overloading Helicopters is dangerous. Image by Helen Krasner

What Can be Done About The Weight Issue?

If your helicopter is too heavy, you need to reduce the weight! In the case of the North Sea helicopters, they need to to this either by carrying fewer passengers or by having lighter workers – but taking fewer workers per trip results in additional expense, and the oil companies are reluctant to do it. Hence the recent emphasis on oil workers losing weight, with fitness classes being arranged for them, and other initiatives.

Helicopter Overloading: Major Issue

Overloading is a major issue for helicopters, in all types of commercial flying. This latest news item has merely clarified what can be an on-going problem for helicopter pilots.

Resources:

Eurocopter. Superpuma. (2013). Accessed March 18, 2013.

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