Northern Rescue currently operates two Leonardo AW169s and a single BK117 helicopter from Auckland and two S76 C++ helicopters from Whangarei, with a view to operating a full fleet of five AW169 aircraft operating from both bases.

In the past year, several maritime and coastal winch extractions conducted at night put a spotlight on some elements of survival equipment and standard operating procedures (SOPs) that needed improvement. These winch transfers were completed using night vision goggles (NVGs), without assistance from automation, and two tasks were at long range. All the operations were in low light and poor weather conditions.

Crew reports from these, and similar tasks, suggested that current winch role equipment is working well and is largely fit for purpose. However, for the long-range tasks, the immersion suits were found to be an issue. This manifested in that crews both struggled to find appropriately sized suits and the suits’ overall suitability was also brought into question.

ARHT’s winching SOPs have been developed over many years on aircraft with no automation, with pilots expected to fly winch transfers manually. Holding a steady hover for long periods, with limited visual references, can be a significant challenge. Given that the AW169 has levels of automation and is likely to be the sole aircraft of choice in the fleet in the future, night winching SOPs were analyzed to look at how best to utilize the new technology that these aircraft currently offer, minimizing the risk during future operations.

Survival suits review

Survival suits are needed infrequently for overwater tasking when sea and air temperatures fall below set criteria. At both bases, if a correctly sized immersion suit was available, many users felt that they were too bulky, both restricting movement and overheating the wearer while moving around the aircraft cabin or when administering care to a patient. It became quickly evident that ARHT urgently needed to source replacements.

With none of ARHT’s aircraft fitted with floatation, there were also valid concerns that an immersion suit (by design) full of water, would hinder escape from a sinking aircraft. Indeed, during a trial in a helicopter underwater escape trainer (HUET) and witnessing the Lead Aircrew Officer struggling to escape from the submerged module in a company immersion suit, the HUET staff had to stop the trial for safety reasons.

Whilst suits designed for flight crew have storage and movement advantages for some roles, they are significantly more expensive than suits designed for generic use

Three Australasian suppliers were engaged to assess the market. They provided options, with a focus on dry style suits, suitable for occasional use by multiple users. Northern Rescue is a trust with limited funding and over 75 operational staff across both bases. Individually issued suits for occasional use was not considered viable on financial grounds.

It was immediately obvious that whilst suits designed for flight crew have storage and movement advantages for some roles, they are significantly more expensive than suits designed for generic use. Also, a decision would need to be made on the type of neck and wrist seals, with most options seeming to favor neoprene over latex for seals. To start, a trial was conducted using dry suits with latex seals. Some crew reported that the latex seals restricted their blood circulation and they had to be cut to fit individual users. After one neck seal was trimmed to fit a person with a larger neck, that seal was then visibly loose on a similarly sized colleague with a smaller neck, which, in a ditching scenario, would have let in water defeating the purpose of the dry suit.

We then sought feedback from a large offshore operator on their experiences using suits with neoprene seals. Their feedback was positive, and although neoprene can be a tight fit initially, the material eases with frequent use and doesn’t require any cutting to fit an individual. They also thought that neoprene is less susceptible to tearing during donning.

Northern Rescue chose Survitec series 1000 dry suits with neoprene seals to replace the existing immersion suits. Survitec understood that cost was important and recommended that we purchase their passenger suit instead of their flight crew suit from the same series. Although it has less pocket storage, the passenger suit is of similar construction, significantly cheaper, designed for multiple users, and is serviced ‘on condition’ locally, at a low cost.

Our crews must maintain proficiency in both overland and overwater winching techniques

AW169 winching SOPs

A significant amount of our area of operations is either coastal or remote, rugged and often steep bush. Given the nature of the terrain and a lack of dedicated national search and rescue (SAR) helicopters, our crews must maintain proficiency in both overland and overwater winching techniques. All our aircraft are fitted with an external hoist and, although only a small percentage of tasks require it, patient extraction by winch is quite common. Crews need to be prepared to winch in any environment, day or night.

ARHT introduced the AW169 in 2018. It was a significant upgrade in capability and, understandably, the initial focus had to be on building operational experience before revising single pilot instrument flight rules (IFR) helicopter emergency medical services (HEMS) SOPs. Until now, winching SOPs (including transits to and from a scene of SAR) had largely remained unchanged; for most day visual flight rules (VFR) operations, simple still works! But now that the AW169 HEMS operations are well established, there is the spare capacity to develop other areas of operations – such as night over water operations – to better utilize the capabilities of our AW169s.

For winching, the AW169 offered increased payload and power margins, significantly faster winch speeds and, importantly, the potential to use a height hold and/or an auto-hover.

The recent review led to a trial of some basic automated procedures that fully utilized the AW169’s transition and hover modes. Designed to significantly enhance safety in the low level maritime environment at night, the basic concepts worked as expected.

The AW169 hover mode was used to establish a stable hover and the hover height was calculated using aircraft system data that guaranteed fly-away if an engine failed, but also minimized rotor wash on the boat

Since the trial, the transition and hover modes were successfully used on a day task in calm conditions, validating the new SOP concepts for wider use in the maritime environment. A small, six-meter-long pleasure craft had a passenger who had been injured during a fall while crossing a bar. The vessel was too small for normal boat winching techniques, so a stretcher extraction was required. The AW169 hover mode was used to establish a stable hover and the hover height was calculated using aircraft system data that guaranteed fly-away if an engine failed, but also minimized rotor wash on the boat. A hi-line stretcher transfer was completed, with the medical crew commenting on how straightforward and safe the whole evolution felt.

The future?

With a limited training budget and infrequent exposure to procedures, our night overwater SOPs must be robust and easily achievable by a single pilot. As we build more experience using SAR automation, it is hoped that Leonardo will release other features to the AW169, already available for their other helicopters. For instance, those with AW139 experience feel that overwater searches and descents to the hover are greatly simplified by coupled search patterns and the excellent ‘mark on target’ function.

Finally, the use of the radar altimeter (RAD ALT) and hover mode during overland night winch operations would significantly enhance safety in that environment too. Currently, the RAD ALT is not reliable enough over land as it loses lock over grass, which leads to unwanted audio warnings and the activation of the safety fly-up function. We will continue to provide feedback on this to Leonardo and hope for a fix soon