During the pre-departure preparations, one end of a towbar was connected to the nose landing gear of a Boeing 737 aircraft and a pushback tractor was positioned approximately one metre from the towbar's opposite end. A ground engineer subsequently started the tractor with the intention of hooking up to the towbar. When the engineer released the handbrake, the tractor lurched forward and struck the towbar. The force of the impact fractured the aircraft nose landing gear drag brace. The nose landing gear assembly then pivoted back under the aircraft, becoming jammed between the towbar and the aircraft fuselage.
The investigation was unable to determine the reason for the sudden movement of the pushback tractor.
SAFETY DEFICIENCIES: As a result of this occurrence, the Australian Transport Safety Bureau has identified two safety deficiencies.
1. There is a lack of formal training and testing for pushback tractor drivers among some aircraft operators. Factual information In order to be eligible to operate an airside vehicle, there are several requirements to be met. These are specified in the Civil Aviation Regulations (CAR's) and Aerodrome manuals. CAR's schedule 10, requires airside vehicle control as a part of an Aerodrome manual. Training of airside drivers requires compliance with the Rules and Practices for Aerodromes (RPA) section 12 - Aerodrome Vehicle Control, which requires competence in such items as: holding a current State or Territory drivers licence, an understanding of terminology, significance of signs and apron markings, and, use of radio equipment. All applicable Australian airports require compliance with the RPA and issue Authority to drive airside (ADA) and Authority for use airside (AUA) documents as well as guidance material in the form of an Airport Vehicle Control Handbook. Responsibility for the training and operation of specific use equipment, such as pushback tractors, rests with the equipment operator. As such, aircraft operators are responsible for the training and maintenance of appropriate competency standards of pushback tractor operators. During the investigation, it became evident that some aircraft operators have no formal training and competency requirements for pushback tractor operators. Training is conducted primarily on-the-job and no recurrent evaluation is conducted. Additionally, there are a variety of push back tractors used by operators, with differing controls and systems, including essential safety controls, and there are no formal competency requirements for the different equipment types.
2. Pushback tractor safety controls are not of a standard design and are not fitted in standard locations across fleets. Although not a factor in this occurrence, the investigation noted that standard fitment may enhance operational safety. Factual information There are no Civil Aviation Regulations covering the standardised location of safety controls in airside pushback tractors. The International Air Transport Association (IATA) Airport Handling Manual, section AHM 913, Basic Safety Requirements for Aircraft Handling Equipment, paragraph 14.1, Emergency Systems, states: "Emergency engine stop button(s) (red mushroom type) shall be provided. These should be installed at convenient positions on the unit to enable immediate shut-down in the event of an emergency." The investigation revealed that there are a number of different vehicle types, all with various locations and types of emergency stop buttons. Some buttons are not conveniently located and are difficult to operate because their design does not conform to IATA requirements.
The Australian Transport Safety Bureau (formerly the Bureau of Air Safety Investigation) recommends:
R20000046: Australian aircraft operators consider the introduction of formal pushback tractor training and competency standards, which includes all varieties of equipment utilised, and regular recurrent proficiency checks of all pushback tractor drivers.
R20000047: Australian aircraft operators evaluate pushback tractor safety controls for standardised design and location across the fleet, particularly in regard to the International Air Transport Association (IATA) requirements.
LOCAL SAFETY ACTION: Although the operator currently has no requirement for recurrent testing of drivers on each particular vehicle for which an airside licence is held, its Airport Services Department is presently addressing this aspect.
