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Improving Ditching Survivability

Occupants of helicopters that ditch into water have a good chance of surviving the impact with only minor injuries.


March 8, 2013
By Carroll McCormick

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Occupants of helicopters that ditch into water have a good chance of surviving the impact with only minor injuries. They also stand a good chance, sadly, of drowning before they can escape the wreckage, according to accident research. Helicopter underwater emergency breathing apparatuses (HUEBA) give passengers extra time to escape, but only if training prepares them to act correctly and quickly in such unusual and highly stressful conditions.

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A revolution in where to learn how to use compressed air during helicopter ditching training began this February in Nova Scotia. (Photo courtesy of SSTL)


 

Buoyed by the conclusions of a study carried out last year in Nova Scotia that tested alternative HUEBA training methods, in early February six instructors at Survival Systems Training Limited (SSTL) in Dartmouth, N.S. began using a new way to instruct students in the use of HUEBA in its helicopter ditching training programs. Instead of teaching students how to use HUEBA while sitting in a shallow-water trainer, essentially a chair that rotates them under the water, instructors are now teaching students how to use HUEBA as part of their full-scale helicopter simulator training.

“This was the first time on the planet offshore personnel have been in the escape trainer with compressed air,” said John Swain, owner of SSTL.

Alana MacLellan was in the first group of students to take the refined program. A registered nurse with Atlantic Offshore Medical Services, she works on the Sable Offshore Energy Project’s Thebaud gas platform off Sable Island. This was her third ditching course.

MacLellan compares the first two, which were breath-hold training sessions in the full-scale simulator, with the Feb. 6 session focused on using compressed air. “The breath-hold sessions were anxiety-producing. My anxiety came in when I had to hit a window out. I cannot describe the difference in the experience.

“For the first time, doing the underwater ditching course, I could comprehend every step of the course. I no longer felt any panic. Now, I have a comfort in how to use the compressed air when the helicopter is turning. It made the training so much more realistic. It was an excellent experience.”

The study showed that integrating HUEBA training with full-scale simulator ditching survival training improved retention of the training a month later. The expectation then, is that passengers will have better recall of their training in the event of a crisis that lands them in water and will therefore be more likely to escape submerged helicopters with their lives.

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A study showed that integrating compressed air and egress training is superior to part-task training. (Photo courtesy of SSTL)


 

This conclusion validated what Swain has long believed. “At SSTL we believe in whole-part learning. Bringing all the sequences together and having the proper sequencing profile maximizes the training outcomes,” he said.

Encana Corporation commissioned and funded the study and SSTL lent its facilities, trainers, volunteer students and expertise. Dalhousie University scientists designed and ran the study, and collected and analyzed the data. The 42-page study is titled Investigation of Emergency Breathing Apparatus Skill Set Knowledge Transfer Between Helicopter Underwater Escape Training Simulators. SSTL has posted an abstract of the study on its website and will provide the full study upon request.

“We proved that getting the HUEBA training in a full-scale simulator is the best way,” says Swain. “This finding will change the standards of safety training and will have implications for offshore training programs.”

SSTL presented the results of the study in February to the Qualification for Safety Training and Certification subcommittee of the Canadian Association of Petroleum Producers (CAPP). Swain is confident the subcommittee will consider changing the training standards as a result of the study.

Training for civil organizations in the use of HUEBA began in 2009, the year that Canadian oil and gas companies committed to carrying compressed air emergency breathing systems in helicopters. HUEBA training has been done separately from full simulator training because of what the study refers to as a perceived risk that trainees might experience a gas embolism while using HUEBA. In order to comply with CAPP guidelines, training schools use shallow-water trainers that ensure that students are submerged to a depth of no more than about 100 centimetres while using HUEBA.

(An inverted full-scale helicopter simulator submerges students to a depth of about 160 centimetres.)

The guidelines have two consequences: HUEBA training cannot be integrated with the rest of full-scale simulator training; and students are not required to demonstrate HUEBA skill proficiency in a full-scale simulator.

It is well understood that part-task training, of which this way of teaching HUEBA skills is an example, is weak pedagogy. The study authors write, “Consistent findings indicate that during the development of motor programs, movements practiced in the simulated environment should closely match those that will be used in a real environment . . . current offshore employees . . . are not given the chance to combine all of the skills associated with underwater escape and the use of emergency breathing systems.”

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Alana MacLellan was one of the first students in the world to be taught how to use compressed air while inside a full-scale training simulator. (Photo courtesy of SSTL)


 

What about the fear of gas embolisms while using HUEBA in deeper water? As part of the study, CAPP commissioned a diving medical doctor to examine all possible medical complications associated with doing HUEBA training in a full-scale simulator. He concluded that there was minimal risk. The authors could only find one officially reported case of compressed gas embolism while training with HUEBA and it was considered to be a result of improper use of the system.

Having found ample confirmation in the literature for the value of integrating different elements of training, and having assuaged concerns about gas embolisms, the business of conducting the study could begin.

Because reading scientific papers is an acquired skill, here are the highlights of the study and conclusions, minus most of the methodological and statistical palaver.

The study had three primary goals: to determine whether integrated HUEBA training would result in a higher success rate in correctly using HUEBA during egress than part-task HUEBA training; to determine whether military-style overtraining would lead to even better performance; and to examine whether integrated training improved performance, that is retention, in tests 30 days after training.

The researchers created four groups, with either 29 or 30 volunteers. The control group, Gc, received the current offshore training standard for helicopter underwater egress training (HUET). They began with four training trials in the full-scale simulator, followed by two HUEBA exercises in the shallow-water trainer.

The second group, Gp1, did two HUEBA exercises in the shallow-water trainer, then additional HUEBA training in the full-scale simulator integrated with the egress training. This group’s training represented one version of the proposed new HUET/HUEBA training standard.

The third group, Gp2, trained according to a second version of the proposed new HUET/HUEBA training standard. It was identical to that taught to Gp1, but with one twist: Instead of receiving HUEBA training in the shallow-water simulator, they simply floated on their backs, and instructors tilted them back until their upper torsos and heads were fully under the water. This twist let the researchers explore the difference between this simple method of shallow-water HUEBA training and the shallow-water simulator, for which little assessment research exists.

The fourth group, Gm, trained to a more military-level training standard. The training was the same as that undergone by Gp1, except that Gm did four HUEBA training exercises in the shallow-water trainer and four integrated HUEBA/HUET egress exercises in the full-scale simulator.

To test retention, the researchers retested all of the volunteers 30 days after their initial training, rating their performance (egress speed and use of the HUEBA) in the full-scale simulator.

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SSTL instructor Matt MacVicar teaches Tiffanny Fewer how to use compressed air in a shallow-water trainer before taking it into the full-scale simulator for egress training. (Photo courtesy of SSTL)


 

The researchers made these key findings: Initial training of HUEBA skills influenced how the volunteers used the system during the retest. Gc participants, who did the breath–hold trials (egress training in the full-scale simulators without using HUEBA) were significantly less likely to use HUEBA during retention testing and required significantly more assistance during egress. In fact, 23 per cent of Gc did not use their HUEBA during the egresses during the retention tests. Twenty per cent of Gc participants also committed task-sequencing errors in the retention test; for example, starting HUEBA tasks before bracing for impact or disconnecting the seat harness before inserting the HUEBA demand valve.

About 10 per cent of the Gp1 and Gp2 volunteers, and none of the Gm volunteers, failed to use their HUEBA. These three groups required less assistance during egress than did Gc.

The researchers also observed that Gc, which received the HUEBA training after the full-scale simulator training, were less likely to pay attention to the HUEBA instruction than the other groups. Gc seemed to regard the HUEBA training as an afterthought. The other groups, which received HUEBA training before the full-scale simulator training, appeared to pay closer attention to the HUEBA training.

In addition to the main findings, there were other revelations; for example, video analyses showed that a number of participants had difficulties with their nose plugs and face seals on the immersion suits. This equipment may need a rethink for future designs. Female volunteers required more assistance in opening the exit. That there is a strength component to jettisoning push-out exits, and smaller people have somewhat more difficulty, suggests another problem that needs attention.


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