Safety Issues
Safety Study of Survivability in Seaplane Accidents
Of the 234 fatal accidents examined in this section, 96 (41%) occurred during the take-off phase, and 87 (37%) occurred during the approach and landing phase. In 48% (103) of the 216 fatal accidents where the accident site was described fully in the occurrence records, the aircraft terminated in the water. Less than 10% of the 276 occupants involved in these 103 accidents escaped unhampered from these aircraft.
This study looked specifically at such questions as:
- Did the deaths occur predominantly as a result of impact-related forces, or as a result of post-impact drowning?
- To what extent were lap belts and shoulder harnesses used?
- Did the drownings occur in the cabin as a result of egress difficulties or did they occur outside the aircraft?
- Were personal flotation devices available to the occupants? If so, were they used and were they effective?
Emergency Egress
Of the 168 occupants (including pilots and passengers) who died in the 103 accidents known to have terminated in the water:
- 118 (70%) were located inside the aircraft.
- 37 (22%) were located outside the aircraft.
- 3 (2%) were found onshore.
- Half of the occupants drowned while trapped in the confines of the cabin.
Of the 63 pilots who died:
- 49 (78%) were located inside the aircraft.
- 10 (16%) were located outside the aircraft.
- One (2%) was found onshore.
The aircraft fuselage often buckled during impact, bending doors and door-opening mechanisms. Aircraft sometimes flipped upside-down, making it difficult to maintain situational awareness. The flaps, which are at least partially lowered on most aircraft during take-offs and landings, may have prevented egress through outward-opening exits. Disoriented occupants may have panicked as icy cold water rushed into the cabin in the seconds following impact. Some of the aircraft involved in water-impact accidents did not have a rear exit, making evacuation for the rear-seat passengers difficult. In these cases, the only egress route for passengers would have been to crawl over the front seats and through the crew door(s). Actuating a simple door-opening mechanism can become an almost impossible task in cold dark water when the aircraft cabin is vertical or upside-down. This may be compounded by the fact that the opening mechanism of some doors is not so simple (with more than one handle or lever to actuate) and few are standard.
A 1988 study cited eight occurrences in which the occupants exited the aircraft successfully but drowned attempting to swim to shore. The report found evidence that "occupants sometimes drown while attempting to reach life jackets stowed in the rear of the cabin or under seats. Often the aircraft became inverted in the water, suspended by the floats. The occupants then swam to the surface whereupon one would dive back to the aircraft to retrieve the life jackets."
Clearly, successful emergency egress is critical is surviving seaplane accidents.
Personal Restraint Systems
Crashworthiness studies conducted in the United States and Canada during the past decades have consistently concluded that the probability of surviving impact forces is significantly enhanced if occupants of small, general aviation aircraft are wearing shoulder harnesses.
Passengers who are restrained during the impact sequence stand a better chance of maintaining consciousness and successfully exiting a sinking aircraft. An effective restraint system may secure the occupants of the aircraft during even cart-wheeling impact forces, better enabling them to find the exits if the aircraft comes to a stop inverted and begins sinking in the water.
Personal Flotation Devices
As shown earlier, only 11% of the fatalities in the seaplane accidents terminating in the water were attributable to the impact forces. The majority of the victims survived the impact but subsequently drowned – with most trapped in the aircraft.
However, drowning was also the most common cause of death (86%) of those who exited the aircraft. Personal flotation devices would probably have saved the lives of many who drowned outside the aircraft.
The instinct of persons in an inverted cabin of an aircraft that is sinking in cold dark water is to get out as soon as possible, without fumbling for a life jacket. If they were wearing a life jacket and managed to find an open exit without the egress being hampered by clothes or the life jacket, then their chances of survival would be considerably enhanced by the personal flotation device.
A video produced by Transport Canada demonstrates that it is almost impossible for even a healthy person in a controlled test environment to don a life jacket in cold water.
This demonstration tends to support an earlier study which found not a single instance in which the occupants donned life jackets after the accident and prior to evacuating the aircraft.
It is often difficult, after a fatal accident, to determine the role that personal flotation devices might have played. In many of the otherwise survivable fatal accidents, the occupants may not have gotten out of the aircraft due to a combination of impact injuries, confusion, and panic.
In any event, life jackets for seaplane occupants can undoubtedly best serve their purpose if:
- They are worn during take-off and landing.
- They do not hamper the movements of the wearer because of their size and configuration.
- They do not provide flotation until activated by the wearer.
Passenger Briefings
As suggested earlier, passengers may have difficulty locating their life jacket and operating the aircraft's exit mechanisms. Accordingly, the Board believes that a demonstration would be more effective,particularly when the actuating mechanisms for doors, windows and emergency exits are complex or non-standard.
Cabin Loading
The extent to which there was unrestrained internal cargo or baggage in the accident aircraft might explain why many occupants failed to exit aircraft involved in survivable accidents.
Conclusions
While it is not clear why many occupants of seaplanes involved in survivable accidents fail to safely egress, a good understanding of the location and operation of emergency exits, emergency equipment and life jackets may be essential to survivability.
Industry practices with respect to flying with unrestrained cargo may be exacerbating the consequences of upset on the water by trapping occupants in the cabin.
This study concludes with TSB recommendations in areas such as Personal Flotation Devices, Personal Restraint Systems, Passenger Briefings & Compliance.
Safety Management Systems (SMS)
The Transportation Safety Board of Canada concludes that Transport Canada does not always provide effective oversight of aviation companies transitioning to safety management systems, while some companies are not even required to have one. This includes the lessons to be learnt for Sport and Recreational pilots.
Background
Safety Management Systems (SMS) principals allow aviators on their own to identify hazards, manage risks, and develop and follow effective safety processes. Canada's large commercial carriers have been required to have an SMS since 2005. However, for smaller operators, such as those which do aerial work or provide air taxi or commuter services, implementation has been delayed to provide additional time to refine procedures, guidance material and training. A large segment of the aviation population however (sport and recreational pilots) which could significantly benefit from the industry’s transition to SMS has gone unaddressed.
Having said this, and in fairness to our responsible regulator, it has never been the intention or mandate of Transport Canada’s SMS implementation plan to include sport and recreational pilots. This being said however, we are missing a tremendous safety benefit to this segment of the aviation population if we keep these important “lessons learnt” at the commercial aviation level.
Safety Management System is simple a safety management tool in which the operator (in this case, the sport or recreational pilot) continually examines the way in which the aircraft is being operated and actively searches for weak areas in their own “personal safety systems” Questions such as:
- Am I current?
- Can I do it safer?
- Am I as safe as I can be?
- Have I identified the particular RISKS involved in my own flight activities?
- Am I managing those risks effectively?
- Can I improve my safety performance?
- What have I learned from others mistakes?
- What have I learned from my own mistakes?
- Am I using my aviation educational and support recourses regularly?
Solution
An understanding and appreciation of the fact that SMS is simply a more effective way to ensure that any pilot’s operation and environment is as safe as it can be. If gaps in our personal safety system are discovered, that they are addressed in a way that ensures that they are addressed and that they do not reoccur.
Smart Pilot Remarks
SMS is a proven, systematic and effective way in which safety can be managed. Whether you pilot an ultra-light or a Boeing 777, we need to continually ask the questions listed above. While mass, momentum and gravity and human behaviour are the predominant universal forces that all pilot’s deal with, the price we pay for the freedom of flight is constant vigilance.
Landing Accidents and Runway Overruns
Landing accidents and runway overruns continue to occur at Canadian airports and involve both are air carriers and general aviation pilots.
Background
Millions of landings occur each year on Canadian runways. Rain, snow, ice or slush can contaminate these runways and affect the landing distance and aircraft controllability. Pilots are required to calculate landing distance before each landing. To do this, they need to have an accurate report of runway surface conditions. If this information is not available, landing distance calculations could be incorrect, putting aircraft at risk of running off the end or the side of the runway.
If this happens, it is important that an aircraft have an adequate safety area beyond the runway's end. At some airports, however, this is not the case, and the terrain beyond the end of the runway could contribute to aircraft damage and injuries to passengers and pilot. This area, therefore, must be sufficiently clear of obstacles and properly graded.
The Transportation Safety Board of Canada (TSB) has investigated a number of landing accidents and incidents that highlight the need for runway surface condition reporting and safety areas. Moreover, since the TSB first placed this issue on its Watchlist, the number of accidents of this type every year has not significantly decreased.
In 2010, there were 12 such accidents, and in 2011, there were 9.2 Meanwhile, in Canada, there is no requirement to meet international standards and recommended practices for safety areas contained within the runway environment.
Solution
In bad weather, pilots need to receive timely information about runway surface conditions. Furthermore, airports need to lengthen the safety areas at the end of runways or install other engineered systems and structures to safely stop planes that overrun.
Smart Pilot Remarks
Achieving the smooth and seamless transition from flight to ground operation is the key to achieving a safe and successful approach and landing phase to all of our flight activities. Obviously, staying within the confines of the landing surface is ultimately important but every pilot needs to assess 3 vital issues during the phase of flight.
- The approach area, obstructions and visual approach angle.
- The landing surface, length, width, texture and possible contamination, and
- Runway environment including ends, sides and taxiways and infield.
Risk of Collisions on Runways
There is an ongoing risk of aircraft colliding with vehicles or other aircraft on the ground at Canadian airports.
Background
Airport operations require aircraft and vehicles to move between ramps, taxiways and runways. Sometimes this movement creates conflicts between aircraft, or between aircraft and vehicles. This can also happen when aircraft or vehicles mistakenly occupy an active take-off or landing area.
In a nine-year period from 2001 to 2009, there were 4140 of these conflicts, known as runway incursions, nationwide. Given the millions of take-offs and landings each year, incursions are rare, but their consequences can be catastrophic.
Since the Transportation Safety Board of Canada (TSB) first placed this issue on its Watchlist, the number of these occurrences has not decreased.
In 2010 there were 351, followed by another 446 in 2011. The Board continues to investigate these occurrences because the risk persists. There are ongoing efforts by both the industry and the regulator to share data and other information, and to improve local airport procedures; however more work in this area is required. In particular, few new technological defences have been seriously considered or implemented in Canada.
The TSB has made findings and reported publicly on the risk of collisions on runways. The Board remains concerned that incursions and the risk of collisions will continue until better defences are put in place.
Solution
Improved procedures and the adoption of enhanced collision warning systems are required at Canada’s airports.
Smart Pilot Remarks
Improved facilities and better technology is always helpful but the most effective tool that any pilot possesses in order to anticipate and avoid runway/taxiway incursions are their eyes, ears and experience. Making sure that the runway is clear is only half the battle but unfortunately this is where many pilots stop observing. Is the runway clear … “and is it likely to remain clear” is the question to be asked which will help to address this very important safety issue.
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We would like to acknowledge the financial support of the Government of Canada for this initiative through the Search and Rescue New Initiative Fund (SAR NIF).