Spin--Loss of Directional Control-Lac Saint-Francois, Quebec - 18 July 1998

Laurentide Aviation Cessna 152 C-GZLZ 

Safety Action Taken
(as presented in the TSB Report)

On 14 March 2000, Cessna notified the TSB that it had designed a rudder horn stop bolt with a larger head diameter to prevent over-travel of the rudder following a hard rudder input. Cessna has notified the Federal Aviation Administration (FAA) Aircraft Certification Office about this matter and expects to issue a Service Bulletin offering the new configuration rudder stop bolt for all Cessna 150s and 152s built after 1966. A time frame for these actions was not specified.

On 09 May 2000, Transport Canada issued Service Difficulty Alert (SDA) No. AL-2000-04 following information gathered during the tests carried out at Saint-Hubert on 22 February 2000. The SDA discusses the accident circumstances and outlines details regarding the inspection of the rudder control system.

Safety Action Required
(as presented in the TSB Report)

While stated action by Cessna to develop a Service Bulletin designed to prevent over-travel of the rudder is appropriate, the Board is concerned that, since the proposed Service Bulletin will be voluntary, not all Canadian-registered Cessna 150s and 152s will be modified. Therefore, the Board recommends that:

The Department of Transport issue an Airworthiness Directive to all Canadian owners and operators of Cessna 150 and 152 aircraft addressing a mandatory retrofit design change of the rudder horn stop bolt system to preclude over-travel and jamming of the rudder following a full rudder input. (A00-09)

Transport Canada's Response :

Transport Canada (TC) is responsible for regulating the airworthiness of aircraft operated in Canada. Transport Canada has been in continual discussions with the United States Federal Aviation Administration (FAA), which is the state of design airworthiness authority responsible for the Cessna 150 and 152 aircraft. The FAA informed Transport Canada that Cessna has not yet developed a retrofit design change. Cessna is, however, planning to provide a product improvement kit to modify the rudder system stops on these aircraft.

To further ensure the safety of the Canadian Cessna 150/152 fleet, Transport Canada has issued Emergency Airworthiness Directive (AD) CF-2000-20 dated August 2, 2000 to be effective August 4, 2000. The AD prohibits intentional spins and incipient spins until an airworthiness inspection of the rudder system is complete and imposes thereafter an inspection every 110 hours or 12 months, whichever occurs first. The FAA has not taken such a mandatory action but is cognizant of Transport Canada’s action.

When a modification is made available by Cessna, Transport Canada, together with the FAA, will review the modification and assess whether mandatory retrofit is appropriate.

Any mandatory airworthiness actions to retrofit Cessna 150 and 152 aircraft with newly designed rudder horn stop bolt systems will likely take considerable time to complete. In the meantime, these aircraft will be flying with a known safety deficiency. The circumstances of this accident suggest that the serious implications of the broken or missing rudder cable return spring were not fully understood. Moreover, the possibility of an irreversibly jammed rudder during intentional spin entry by full rudder deflection was not understood until this accident investigation was completed. Therefore, the Board recommends that:

The Department of Transport, in conjunction with the Federal Aviation Administration, take steps to have all operators of Cessna 150 and 152 aircraft notified about the circumstances and findings of this accident investigation and the need to restrict spin operations until airworthiness action is taken to prevent rudder jamming. (A00-10)

Transport Canada's Response :

The Cessna 150 and Cessna 152 are primary flight training aircraft. There are approximately 1,500 such aircraft in Canada and an estimated 21,000 of these aircraft in service world-wide. Investigations by Transport Canada and the FAA have not found evidence of a previous occurrence of such an accident. There is, however evidence that under certain conditions, the rudder of the Cessna 150/152 aircraft can over-travel the rudder stops. This would be a prerequisite to the rudder jamming in a fully deflected position.

To ensure awareness, Transport Canada issued Service Difficulty Alert No. AL-2000-04 ( HTML or PDF ) dated May 9, 2000 to owners, operators and the aviation maintenance community, informing them of the circumstances and safety issues related to this accident. The Service Difficulty Alert, similar to FAA ACE-118W ( HTML or PDF ), recommends a detailed inspection of the rudder control system.

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