Kelowna Flightcraft Air Charter Flight 284: Aft Cargo Door Opens After Takeoff

Incident Overview and Immediate Response Kelowna Flightcraft Air Charter Ltd. Flight 284 (KFA284), a Boeing 727-227 with registration C-GJKF and serial number 21042, departed Regina, Saskatchewan, on a scheduled cargo flight to Hamilton, Ontario. The aircraft was chartered by Purolator Courier, which also provided ground handling. Shortly after rotation, the crew observed that the aft cargo door warning light was illuminated, followed by irregular indications from the number 3 engine. The crew shut down the number 3 engine and diverted to Saskatoon, Saskatchewan, at an altitude of 10,000 feet. The aircraft landed safely at 0710 central standard time, with airport rescue and firefighting (ARFF) on standby. ## Damage and Injuries The aft cargo door was found open, with the door handle stowed in the locked position. There were no injuries. The aircraft sustained minor damage to the aft cargo door hinges. No damage was found to the door structure or latching mechanism. ## Maintenance, Crew, and Environmental Factors Records indicated that the aircraft was maintained in accordance with Kelowna Flightcraft Air Charter Ltd.'s approved maintenance control system. The flight crew was certified, qualified, and met crew rest requirements under existing regulations. Weather and runway conditions were not factors in the occurrence. ## Recorder Data Flight data recorder (FDR) information was retrieved. The FDR was an older model capable of recording only 11 parameters and did not record annunciator panel light status. FDR data showed a sudden fluctuation in the number 3 engine pressure ratio (EPR) approximately 2 minutes 30 seconds after rotation, at 7,600 feet above sea level. The cockpit voice recorder (CVR) was a 30-minute tape unit, and details concerning the occurrence flight were overwritten during the flight. ## Engineering Analysis The cargo door, hinges, latch cams, and microswitch were sent to the TSB Engineering Laboratory for further analysis. Inspection and bench testing of the door and microswitch revealed no anomalies. The aft cargo door is equipped with an instructional placard indicating how the door should be locked. The instruction reads: “LEAVE HANDLE EXTENDED WHEN LOCKING DOOR.” Discussions with the operator indicated that the placard was viewed as an instruction. The manufacturer viewed the placard as a caution only, intended to avoid damage to the door mechanism. The wording on the instructional placard can be misleading. Literal adherence to the instruction suggests that the door is locked when the handle is extended. It was determined that the wording on the instructional placard did not contribute to the occurrence. ## Loading, Door Status, and In-Flight Behavior The loading and unloading of KFA284 was carried out during the early hours of the morning, in the dark. It is likely that the cargo door was closed but not locked. Despite the position of the door handle, an unlocked aft cargo door in a closed position may appear to be locked, especially from a distance in the dark. After the aircraft became airborne, aerodynamic forces caused the unlocked aft cargo door to open. The door is located in close proximity to the number 3 engine inlet. Opening of the door would have produced an interruption in air flow to the number 3 engine inlet, resulting in irregular EPR indications. It is likely that the slip stream produced enough force in flight to close the extended door handle. It was determined that the geometry of the door and latching mechanisms does not allow the aft cargo door light to extinguish unless the cargo door is properly closed in place and locked. Functional tests of the aft cargo door warning system and examination of the microswitch suggest that the warning system was functioning normally. Because of the relative position of the door warning and APU caution lights, the two lights can be confused with one another. If the door warning light is mistaken for the APU light (with the APU shutdown), it is possible that the door warning may not be noticed until after takeoff, where it is again required to be checked. ## Findings and Safety Action The aft cargo door was most likely closed but not locked before takeoff, and it opened after departure due to aerodynamic forces. The ground crew did not check the aft cargo door for security before takeoff, and as a result, the door was not locked. The flight crew members did not discover the unlocked aft cargo door during the walk-around inspection, nor did they notice the aft cargo door warning light before departure. Ramp attendants were not required by their procedures to ensure that the cargo doors were properly closed. The instructional placard on the aft cargo door describing how to lock the door contained misleading instructions. After the occurrence, Purolator Courier amended its ramp operations manual by introducing a checklist that requires ramp attendants to ensure the security of cargo doors. The checklist is required to be initialled by ramp personnel after the completion of each aircraft loading operation. On 27 February 2007, the TSB issued two occurrence bulletins concerning the instructions on the cargo door placard and the cargo door closing procedures. The purpose of occurrence bulletins is to apprise Transport Canada and others in the aviation community in a timely manner of certain information that may raise potential operational or technical concerns. This report concludes the Transportation Safety Board's investigation into this occurrence. Consequently, the Board authorized the release of this report on 08 November 2007.