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.