Search

Background: Helicopter underwater escape training (HUET) carries a potential for injury and this paper identifies the injury rate., Method: A marine survival training school registry of all students trained between 2005-2012 in HUET and the coinciding accident records were examined., Results: There were 8902 students trained in a helicopter underwater escape simulator for a total of 59,245 underwater escapes. There were 40 cases where only first-aid was required and 3 serious injuries (a laceration requiring 5 sutures, 1 dislocated shoulder, and 1 water aspiration requiring hospitalization). There were no deaths and no problems reported with using the Emergency Breathing System (EBS) or Air Pocket. Of the injuries, 11 were due to the student using a poor escape technique. The overall probability of injury was 0.74 per 1000 ascents., Conclusions: In HUET training, there is a very low injury rate with almost no significant severity. Although not scientifically proven, this would suggest that the low incident rate is due to good medical screening and the attention given by instructors to anxious students. Compared to other training such as diving, parachute jumping, and submarine escape training, the rate of injury was considerably lower.

Introduction: According to 40 yr of data, the fatality rate for a helicopter crash into water is approximately 25%. Does warning time and the final position of the helicopter in the water influence the survival rate?, Methods: The National Transportation Safety Board (NTSB) database was queried to identify helicopter crashes into water between 1981 and 2011 in the Gulf of Mexico and Hawaii. Fatality rate, amount of warning time prior to the crash, and final position of the helicopter were identified., Results: There were 133 helicopters that crashed into water with 456 crew and passengers. Of these, 119 occupants (26%) did not survive; of those who did survive, 38% were injured. Twelve died after making a successful escape from the helicopter. Crashes with < 15 s warning had a fatality rate of 22%, compared to 12% for 16-60 s warning and 5% for > 1 min. However, more than half of fatalities (57%) came from crashes for which the warning time could not be determined., Discussion: Lack of warning time and how to survive in the water after the crash should be a topic for study in all marine survival/aircraft ditching courses. Investigators should be trained to provide estimates of warning time when investigating helicopter crashes into water.

Introduction: When a helicopter ditches the majority of crew and passengers have to make an underwater escape. Some may not be able to hold their breath and will drown. For at least 15 yr, military aircrew have been trained to use a scuba system. In the offshore oil and gas industry, there has been more caution about introducing a compressed air system and a rebreather system has been introduced as an alternative. Recently, Canadian industry and authorities approved the introduction of Helicopter Underwater Emergency Breathing Apparatus (HUEBA) training using compressed air. This communication reports the training of the first 1000 personnel., Methods: Training was introduced in both Nova Scotia and Newfoundland concurrently by the same group of instructors. Trainees filled out a questionnaire concerning their perceived ratings of the ease or difficulty of classroom training and the practical use of the HUEBA., Results: Ninety-eight percent of trainees found the classroom and in-water training to be "good/very good". Trainees found it to be "easy/very easy" to clear the HUEBA and breathe underwater in 84% and 64% of cases, respectively. Divers reported a greater ease in learning all the practical uses of the HUEBA except application of the nose clip., Discussion: There were problems with the nose clip fitting incorrectly, and interference of the survival suit hood with the regulator, which subsequently have been resolved. When carefully applied, the introduction of the HUEBA into training for offshore oil and gas industry helicopter crew and passengers can be safely conducted.

Background: When a helicopter crashes or ditches into water the crew and passengers must often make an escape from underwater and a number of the occupants do not survive. This paper examined fatality rates, human factors problems with escape, and causes of death in Canadian civilian registered helicopter accidents in water (1979-2006)., Method: Data obtained from the Transportation Safety Board of Canada was reviewed. Key issues such as fatalities, injuries, warning time, sinking, and inversion were examined., Results: There were 46 helicopters that ditched into water. There were 124 crew and passengers involved. Of those, 27 (23%) crew and passengers died. Lack of warning time (55%), rapid sinking (72%), and inversion (35%) were the most common issues in the accidents., Conclusion: Survival rates for Canadian registered helicopter accidents into water (78%) show little change from previously reported worldwide data. Lack of warning time, rapid sinking, and inversion were the significant factors in the survival rate. The practical implication is that crew and passengers involved in planned flights over water must wear all the life support equipment on strap-in and not have it stowed on the back of the seat or in the cabin.

Introduction: A systematic desensitization program designed to help aircrew who have a phobic anxiety of the Helicopter Underwater Escape Training (HUET) has been developed., Case Presentation: A student pilot presented with a severe phobic anxiety of the HUET course--a result of a being trapped underwater on a marine survival training course. A treatment team was assembled and concluded his phobia could be treated by a systematic desensitization method. An exposure matrix of graded difficulty of in/underwater escapes was performed over 2 d. The student reported that his confidence increased and anxiety reduced as he became accustomed to being strapped into a seat in the escape trainer while wearing increasingly difficult levels of equipment which increased the difficulty of escape, such as taking away nasal protection and goggles. At the end of Day 1, he was able to jettison the exit door/hatch while inverted underwater with a facemask and dressed in a simple coverall. At the end of Day 2, without nasal protection, inverted underwater, wearing full military equipment, he was able to cross the cabin, jettison the exit door, and successfully escape., Discussion: A systematic desensitization treatment program can be used to successfully treat aircrew for phobia of the helicopter underwater escape trainer.

Background: When a helicopter ditches into water, it immediately inverts due to the weight of the engines and then fills with water. Locating the emergency exit for escape under such conditions is a difficult task. A new lighting system for an escape exit has been developed that illuminates on contact with water. The detectibility of the lighting was investigated under varying conditions of ambient illumination, water turbidity, and viewing distance., Method: A total of 288 underwater detection trials were carried out by 9 subjects with an illuminated hatch placed at 2 distances (1.5 m and 3.1 m), under 2 ambient illuminations (bright: > 3000 lux and dark: < 0.1 lux), and in 2 conditions of water turbidity. The water temperature was 12 degrees C for all conditions., Results: At 1.5 m, the lighting system was detectable in less than 1.5 s by all subjects in both clear and turbid water and under both bright and dark conditions. At 3.1 m, the lights were detectable in both clear and turbid water under the dark condition and in clear water under the bright condition. However, the lighting was not reliably detected in turbid water under bright condition., Conclusions: The system met original design requirements in terms of detectibility at 1.5 m. The detection time was always under 1.5 s. It could also be detected at 3.1 m in clear and turbid water, under dark conditions. However, the detectibility at 3.1 m in turbid water, under bright condition was less reliable.

Background: Following a helicopter ditching in water, the survival rate of individuals not mortally injured by the impact ranges from 50-85%. One possible cause for this low survival rate is that the crew and passengers cannot hold their breath underwater long enough to make the often difficult escape from an inverted and submerged helicopter., Methods: We investigated pulmonary function, breath-holding times in air (BHTa) and water (BHTw) of 228 students enrolled in offshore survival courses required to work in either the offshore petroleum industry or in military marine aviation. Comparisons were performed based on occupation, SCUBA experience, and smoking., Results: In 25 degrees C pool water, the overall BHTw ranged from 5.4 to 120 s with a median of 37 s. Of the 228 subjects, 34% had a BHTw less than the 28 s required for the complete evacuation of a Super Puma helicopter under ideal conditions. No significant differences in BHTw were observed based on either smoking history (Non-Smoker, 41.5 +/- 21.6 s; Smoker, 37.2 +/- 20.2 s) or occupation (Novice, 37.5 +/- 21.1 s; Offshore, 40.5 +/- 21.1 s; Military, 45.2 +/- 20.9 s). However, SCUBA-trained individuals had a significantly longer BHT, (47.4 +/- 21.6 s) than non-SCUBA (37.6 +/- 20.6 s), as well as a greater force vital capacity (FVC), BHTa, and subjective comfort in water., Conclusions: It is concluded that the inability to breath-hold in emergency situations is a major contributor to the low survival rates of marine helicopter ditchings. Therefore, efforts must be made to both decrease escape times and to increase survival time underwater.

Hypothesis: When a helicopter ditches or crashes in water, unless the buoyancy bags are inflated, it commonly sinks inverted. Thus, crew and passengers must make an underwater escape. It is postulated that later passengers in the escape sequence do not have the breath-holding ability to conduct a successful escape, particularly if the water is cold. This contributes to the 20-50% mortality rate in survivable accidents., Methods: There were 132 immersed subject evaluations which were conducted in daylight and darkness to measure escape times from a helicopter underwater escape trainer, configured to the Super Puma, seated for 15 and 18 passengers. The subjects were highly experienced instructors or Navy clearance divers., Results: The time from when each subject's head disappeared underwater until each subject surfaced and total fuselage evacuation time were measured and any problems hampering escape were noted. Breath-holding for the last subject out ranged from 28 to 92 s. An emergency breathing system was used by a minimum of four subjects each time and a maximum of 11 subjects in one condition. The buoyancy of the survival suit was the principal component that hampered escape., Conclusion: Breath-holding times were too long for the later subjects to escape without resorting to an EBS, in spite of the fact that they were highly trained. For regular crew and passengers flying over water, this would explain the high mortality, etc. Therefore, a new helicopter standard should be developed requiring fuselage design to accommodate total evacuation within 20 s from underwater. For current helicopters, where this cannot be achieved, passengers should be provided with some form of air supply, or, after ditching, the helicopter should be modified so that it will stay afloat on its side and retain an air space in the cabin.

Background: Spatial orientation is based on the integration of concordant and redundant information from the visual, vestibular, and somatosensory systems. When a person is submerged underwater, somatosensory cues are reduced, and vestibular cues are ambiguous with respect to upright or inverted position. Visual cues may be lost as a result of reduced ambient light. Underwater disorientation has been cited as one of the major factors that could inhibit emergency egress after a helicopter ditching into water. One countermeasure to familiarize aircrew with underwater disorientation is emergency egress training. This study examined the relative degree of underwater disorientation induced by the Modular Egress Training Simulator (METS) and the Shallow Water Egress Trainer (SWET)., Methods: There were 36 healthy subjects (28 males and 8 females) who participated in the study. Underwater disorientation was quantified by measuring the deviation of subjective vertical-pointing from the gravitational vertical, time to egress, and subjective reports of disorientation and ease of egress. A repeated measure design was employed with seat position (SWET chair, METS window, and METS aisle) as the sole factor., Results: Subjective response data indicated that the degree of disorientation is rated significantly higher, and the ease of egress is rated worse from the two METS seat positions than from the SWET. This is supported by the findings that subjective vertical-pointing accuracy is worse in the METS seat positions than in the SWET (p < 0.01). The time to egress is longer from the two METS seat positions than from SWET (p < 0.01)., Conclusion: Our results indicate that the METS device is effective for inducing underwater disorientation as provoked by simulated helicopter ditching. disorientation, vestibular, subjective pointing.

Background: To date, there is no standard jettison mechanism for doors, windows, or hatches in ditched helicopters. A new Universal Escape Exit (UEE) has been invented and the performance has been compared with two current in-service systems in a helicopter underwater escape trainer., Method: A total of 416 evacuations were conducted by 40 subjects in two experiments using the Survival Systems Limited's underwater escape trainer., Results: The UEE had a distinct 2-s advantage to escape; and, in the majority of cases, was preferred to a rotating lever or a straight push out system., Conclusions: Further work should continue with UEE development for qualification in an operational helicopter.

Methods: Six subjects who were each wearing a dry immersion suit system were immersed for 1 h in 16 degrees C water in a number of different wave conditions, ranging from still water to 70 cm in height. Physiological and physical parameters were measured in order to calculate the total thermal resistance of the suit system and its components., Results: None of the physiological parameters were affected significantly by the wave conditions, except for skin heat flux, which increased with wave height from 72.0 +/- 1.9 W x m(-2), at 0 cm of height, to 85.5 +/- 2.9 W x m(-2), at 70 cm of height. Wave heights up to 70 cm decreased the insulation (including boundary layer) of the dry suit system by 14%, and the only component of the suit affected by the wave motion was the insulation of the water boundary layer, which decreased by 75%. The body sites that were most affected by wave motion were the head and the trunk, with an average 45% decrement in suit system thermal resistance at those sites at wave heights of 0 to 70 cm. No significant effect was observed at sites on the distal limbs., Conclusion: To simulate open ocean conditions in the laboratory, the standards must take the reduction of suit insulation into account.

Method: Dry and wet evacuations were conducted by 24 male and 19 female subjects from the Nutec Super Puma Simulator into two different types of aviation liferaft., Results: Dry evacuation on the windward side is the method of choice. The non-canopy raft is subjectively and objectively easier to enter both from the helicopter and the sea., Conclusions: The non-canopy raft is the raft of choice, the canopy raft needs a redesign to ensure that it always inflates the correct way and both rafts need a redesign of the painter anchor point. Aircrew should have special training in open water after traditional pool training. A helicopter ditching survival compass has been developed for training all who fly over water for a living.

There are 23 different door, hatch, and window release mechanisms identified in 35 types of helicopters that earn their living over water. There is no standardization of the mechanism within each cockpit or among helicopter types, nor is there any standardization of the location relative to the operation; whether the mechanism matches the task or in which direction the door/hatch/window is jettisoned. New regulations are needed by military and civilian authorities to address the ergonomic confusion.

Methods: There were 23 male and 21 female subjects who conducted a series of evacuations from the NUTEC Super Puma helicopter simulator into an RFD heliraft in the Bergen Fjord. The dry shod and swim-away methods were compared both on the windward and leeward side., Results: The dry shod method is the method of choice, although the swim-away method should be taught as an alternative in the event of imminent capsizing. Irrespective of method, evacuation wherever possible should be on the windward side., Conclusions: Because it is critical for the aircrew to make a split-second decision concerning which method to use, they should have special training in open water after traditional pool training.

The first formal investigation of the problem of location, operation and jettison of escape windows and hatches of helicopters following ditching has been conducted in a new simulator. There were 48 aircrew who attempted 298 escapes using a variety of 24 escape routes and 9 different types of escape hatches. Overall results, while superficially indicating that the task was easy, in fact revealed many unforeseen problems. Specifically, there was no standardization of hatches and levers, there were problems with location and operation of levers principally due to poor design, and an ergonomics study has not been conducted to investigate the problem. Underwater escape training with hatches in position must be mandatory for all who fly off-shore or over water for a living, and further research should be conducted to design a better standard hatch and jettison system.

The immersed clo value of a series of 11 marine work suits has been measured using both humans and a thermal manikin. In still water, there is no significant difference in the measurements. Turbulent water significantly reduces the immersed clo value. The manikin errs on the safe side and consistently overestimates this decrement in insulation, and the reasons for this are discussed. Not intended to replace human physiological testing, the manikin is an excellent apparatus for the examination of conditions not easily or ethically possible to represent using humans. A good fitting suit with efficient neck, wrist and ankle closures which reduce flushing of water is essential to make an effective marine work suit.

A 20 year review of Canadian Forces (CF) aircrew ejection/ditching, survival/rescue times and injury patterns in salt and fresh water is presented. Of the 595 A, B, and C category accidents which have been reviewed (1962-1982), 37 were water-entry. Of the 116 crew which were involved, 38 died (4 in fresh water). The Sea King helicopter is most at risk from sea water immersion, and the single-engine Otter has been the most vulnerable to fresh water immersion. A water immersion can be expected approximately once every 170,000 h of total flying time. In 92% of cases, the crew had less than 1 min warning that immersion was imminent and in 78% had less than 15 s to make a practical response. There were two clinical cases of hypothermia. In the absence of injuries, aircrew trained in water survival, qualified on the Dilbert Dunker, and who are strong swimmers or sports divers, have a better chance to survival. Time to rescue in all cases was under 3 h, and in 16 out of 24 cases crew members were rescued in under 15 min.

This paper reviews the head and neck injuries experienced by Canadian Forces Aircrew who ejected while wearing the DH 41-2 helmet during the period from 1 Jan. 1972 through 31 July 1982. Pre and post-ejection factors, including a review of helmet performance, are presented.

A review of all aircraft accidents and incidents in the Canadian Forces over the last 20 years (1962-1982) has been carried out. There have been 47 cases of serious loss of cabin pressurization in ejection seat equipped aircraft. Altitudes varied from 15,000 to 54,000 ft (4,572-16,459 m). No one aircraft appears to be more vulnerable. The most common cause was problems with the canopy seal (25%). There were three cases of hypoxia and two cases of decompression sickness. No deaths or permanent injuries occurred. Loss of pressurization is an extremely low, but definite risk to the pilot and aeromedical training with practical demonstration in the hypobaric chamber should continue.

A review of all transport aircraft accidents and incidents in the Canadian Forces over the last 22 years (1963-1984) has been carried out. There have been 47 cases of serious loss of cabin pressurization. Altitudes varied from 2133 to 11277 m (7000 to 37,000 ft). The CC 130 Hercules appears to be the most vulnerable (62%). The most common cause was mechanical in origin (70%). There were two definite cases of hypoxia, and oxygen masks were deliberately deployed in nine cases. No deaths or permanent injuries occurred. Loss of pressurization is an extremely low, but definite risk to the pilot and passengers, thus aeromedical training with practical demonstrations in the hypobaric chamber for aircrew and flight attendants should continue.

Protection from hypothermia and drowning are the primary requirements for an immersion suit system during ship, rig, or helicopter abandonment in the North Atlantic. In order to achieve this, the suit must be dry and comfortable. The problems involved in manufacturing such a suit are discussed and the fact is that there is still not a suit in existence that fulfills all the criteria.