Aviation Recommendation A13-03
Assessment of the Transport Canada response to Aviation Safety Recommendation A13-03
Pasenger shoulder harnesses
On 25 May 2012, the Cochrane Air Service de Havilland DHC-2 Mk.1 Beaver floatplane (registration C-FGBF, serial number 168) departed Edgar Lake, Ontario, with 2 passengers and 300 pounds of cargo on board. The aircraft was destined for the company's main base located on Lillabelle Lake, Ontario, approximately 77 miles to the south. On arrival, a southwest-bound landing was attempted across the narrow width of the lake, as the winds favoured this direction. The pilot was unable to land the aircraft in the distance available and executed a go-around. At 1408, Eastern Daylight Time, shortly after full power application, the aircraft rolled quickly to the left and struck the water in a partially inverted attitude. The aircraft came to rest on the muddy lake bottom, partially suspended by the undamaged floats. The passenger in the front seat was able to exit the aircraft and was subsequently rescued. The pilot and rear-seat passenger were not able to exit and drowned.
The Board concluded its investigation and released report A12C0071 on 23 October 2013.
Board Recommendation A13-03 (23 October 2013)
The TSB has found that the risk of serious injury or death is increased for occupants of light aircraft who are not wearing upper-torso restraints or shoulder harnesses. The results of previous safety studies completed by the TSB (SA 9401, TP 8655E) have been more recently supported by a Federal Aviation Administration (FAA) study into fatal and serious injury accidents in Alaska.
A significant portion of the commercial floatplane fleet in Canada was manufactured before shoulder harnesses were required for passenger seats, and remain in this configuration today.
In the event of a seaplane accident, the occupants of the aircraft may drown if they are unconscious; loss of consciousness is normally caused by head trauma. If restrained and protected during the impact sequence, occupants may maintain consciousness and stand a better chance of successfully exiting a sinking aircraft. The use of a three-point safety restraint (safety belt and shoulder harness) is known to reduce the severity of upper body and head injuries and more evenly distribute impact forces.
The TSB has previously recommended (A94-08, A92-01) that small commercial aircraft be fitted with seatbelts and shoulder harnesses in all seating positions. Following these recommendations, changes to regulations were made to require shoulder harnesses in all commercial cockpits and on all seats in aircraft with 9 or fewer passengers manufactured after 1986.Footnote 1 This regulatory change did not address the vast majority of the commercial floatplane fleet, which was manufactured prior to 1986.
The TSB considers that, given the additional hazards associated with accidents on water, shoulder harnesses for all seaplane passengers will reduce the risk of incapacitating injury, thereby improving their ability to exit the aircraft.
Therefore, the Board recommends that:
The Department of Transport require that all seaplanes in commercial service certificated for 9 or fewer passengers be fitted with seatbelts that include shoulder harnesses on all passenger seats.A13-03
Transport Canada's Response to A13-03 (22 January 2014)
Transport Canada has devoted significant effort to seaplane safety. In 2006 a risk assessment team met to analyze the risks associated with egress from submerged aircraft and identify potential risk reduction measures. The team considered the option of making shoulder restraints available to all occupants. The team's analysis showed that this option would not reduce the risks by any significant factor.
On August 22-25, 2011 - TC inspectors, floatplane industry representatives, and aircraft manufacturers formed a Focus Group which undertook a risk assessment and discussed TSB recommendations to determine what would be the best mitigation strategy to improve levels of safety for commercial sea plane operations in an effective and sustainable way. The group discussed the use of shoulder harnesses but concluded other measures offered more promise than mandating shoulder harnesses.
Most commercially-operated seaplanes in Canada are in the normal/utility category. The cabin designs and configurations of most of these likely do not readily lend themselves to installation of shoulder restraints for all passengers without substantial aeroplane redesign and/or structural modification. Most of the aircraft structures are not robust enough to support shoulder restraints in a crash and may hinder egress. Mandating the retrofitting of shoulder restraints for all occupants is not feasible. Each application to install shoulder harnesses would need to be assessed on a case by case basis.
Since fleet-wide installation of shoulder harnesses is not feasible, Transport Canada will continue its efforts at safety education and promotion.
In December 2013, Transport Canada published a Civil Aviation Safety Alert (CASA) on Safety Belts, and an article in the Aviation Safety Letter (ASL) Issue 4/2013 titled “Shoulder Harnesses and Seat Belts- Double Click for Safety”. Transport Canada will also be revising Advisory Circular (AC) 605-004 Use of Safety Belts by Passengers and Crew Members, to align with Federal Aviation Administration (FAA) AC No.21-34.
Board Assessment of Transport Canada's Response to A13-03 (05 March 2014)
The benefits of wearing shoulder harnesses to reduce the risk of incapacitation have been proven. The TSB's recommendation is supported by the results from the study completed by the FAA in Alaska in 2010.
In its response, TC indicated that the cabin designs and configurations of most of the commercially operated float planes in Canada likely do not readily lend themselves to installation of shoulder restraints for all passengers without substantial aeroplane redesign and/or structural modification.
There are approximately 600 aircraft on the Canadian commercial aircraft registry that are potentially operated on floats, certificated for 9 or fewer passengers and manufactured before 1986. Of these aircraft approximately 200 are DHC-2's and 300 are Cessna's. There are already shoulder harness installation kits available for the Cessna's as described in Cessna Single Engine Service Bulletin SEB92-28. Additionally, Transport Canada approved a Limited Supplementary Type Certificate (O-LSA09-360/D) for the installation of rear shoulder harnesses in several DHC-2's in 2009. These facts support the feasibility of retrofitting many floatplane designs with shoulder harnesses.
TC further stated that most of the aircraft structures are not robust enough to support shoulder restraints in a crash and may hinder egress.
TC has not demonstrated that the risk of hindering egress outweighs the benefits of rear-seat shoulder harnesses. Shoulder harnesses in all seating positions for normal/utility category of aircraft have been required by regulation since 1986, and have been installed since that time in similar albeit newer aircraft to the ones previously described. The availability of these installations, the existing kits, and TC issued STC's show that the aircraft structures are robust enough to support these restraints.
Transport Canada has not provided any objective information to demonstrate that it is not feasible to install rear-seat shoulder harnesses. Nor has TC demonstrated that the risk would not be reduced significantly if rear-seat shoulder harnesses were installed.
Because TC's response does not contain details of any action which has been taken or proposed that will reduce or eliminate the safety deficiency, the deficiency will continue to put persons at risk.
Therefore, the response to Recommendation A13-03 is assessed as Unsatisfactory.
Next TSB action
The TSB will follow-up with Transport Canada and await further information about the regulator's planned actions to address the safety deficiency underlying this recommendation.
This deficiency file is assigned an Active status.
- Footnote 1
Canadian Aviation Regulations (CARs), 605.24, “Shoulder Harness Requirements”.
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