Occurrence Details
On 29 November 2021, a Mitsubishi Heavy Industries CL-600-2D24 (Regional Jet Series 900), registration C-GJZV, operated by Jazz Aviation LP as flight JZA767, was departing San Diego International Airport, California, for Vancouver International Airport, British Columbia. The aircraft carried 2 flight crew, 2 cabin crew, and 69 passengers. At approximately 1842 Pacific Standard Time, during darkness, the aircraft took off to the left of the centreline on Runway 27. The left main landing gear wheels contacted three runway edge lights before the trajectory was corrected.
During the climb, the flight crew detected a fuel imbalance they could not correct. They shut down the right engine and declared an emergency. The aircraft diverted to Los Angeles International Airport, where it landed and stopped on the runway at about 1946. No injuries were reported. Emergency personnel noted a deflated left main landing gear tire and smoke from the wheel. Later inspection revealed damage to the No. 1 tire sidewall and two punctures on the left flap.
Runway Misalignment
The investigation examined visibility conditions at San Diego. From pushback to takeoff, the aircraft operated at night in fog, with visibility between ¼ and ½ statute mile and deteriorating. Few visual cues were available. The captain taxied off the lead-on taxiway centreline marking to increase runway distance available for takeoff, further reducing cues. When turning to align with the runway heading, the captain perceived the left runway edge marking as the centreline. The limited and ambiguous visual cues likely met his expectations, resulting in alignment with the left edge rather than the centre.
Runway 27 has a displaced threshold. The investigation found that lining up in displaced threshold areas or conducting intersection departures under degraded or nighttime visual conditions, without confirming lateral position, increases the risk of misalignment or side excursions. San Diego's high volume of operations created a perceived time pressure, and the first officer, completing line-up checks during taxi, did not monitor the taxi progress. He did not recognize the nose was aligned with the left edge when he assumed pilot flying shortly before takeoff.
During the takeoff roll, the left main landing gear contacted and severed three runway edge lights. The flight crew perceived the sounds and vibrations as normal contact with embedded centreline lights and continued the departure. The airport lacked a foreign object debris detection system; debris was not discovered until hours later, posing a risk to other aircraft.
Fuel Imbalance
The fuel imbalance was unrelated to the runway misalignment. It likely resulted from the flight crew inadvertently pressing the gravity crossflow push-button switch instead of the co-located crossflow auto override switch during checklists. This allowed fuel to transfer between wing tanks by gravity when the aircraft banked, worsening the imbalance.
Guidance from Jazz Aviation and the manufacturer (Mitsubishi Heavy Industries Regional Jet Aviation Group) for addressing fuel imbalances was unclear and inconsistent. With the autopilot engaged, the aircraft unintentionally entered a sideslip toward the heavier wing, and the opposite bank was not recognized. The imbalance continued to increase. The checklists did not require closing the gravity crossflow valve after the Gravity Crossfeed Procedure, allowing the open valve to worsen the imbalance during subsequent manoeuvring, at one point exceeding the maximum permissible by more than three times. The crew declared an emergency and diverted.
Post-Occurrence Actions
Following the occurrence, Jazz Aviation LP added warnings to its airport charts for San Diego, highlighting risks of departing from within displaced threshold areas and prescribing measures to verify runway alignment. The operator also issued a company memo on such departures, revised its line-up check procedure, and updated its Gravity Crossfeed Procedure to include more guidance on initiating a sideslip.