With a crew of three and 32 passengers, a Dornier 328-100 was operating a scheduled domestic flight in the Philippines on this day in 2009. The aircraft had taken off from Caticlan-Malay Airport at 11.45 lt (local time) and had Manila-Ninoy Aquino International Airport as its destination, with an estimated arrival time of 12.35 lt.
The aircraft in its final position shortly after coming to a stop (Source avherald.com © AFP)
With the captain as pilot flying (PF) and the copilot as pilot monitoring (PM) the aircraft was offered a visual approach to runway 13 at Manila-Ninoy Aquino International Airport. The weather was good, with a temperature of 31 ºC and west south westerly winds at 14 knots. This was accepted by the crew and the aircraft was configured appropriately and a stable approach was flown, followed by a smooth touch-down on runway 13. Six seconds after touchdown the aircraft started veering to the right, this was countered by the PF by applying left rudder. This was insufficient to stop the aircraft from departing the paved runway surface, after colliding with a taxi light it entered the grass adjacent to the runway.
Estimated runway track and final position (Source avherald.com)
A quick assessment of the situation (the aircraft had departed the runway at a relatively low speed) made the captain decide that an emergency evacuation was not required. All occupants left the aircraft normally via the aircraft's main door. There were no injuries. reported. The runway excursion was reported to the Civil Aviation Authority of the Philippines (CAAP), their Aircraft Accident Investigation and Inquiry Board investigated the incident and in their report gave the following probable cause;
The uneven traction of the nose wheel tires on the ground because of the difference in height, contributed by the cross tail wind which was quite substantial at the time of the incident. (Weather vaning into the wind). Another contributory factor is the incorrect pilot technique used when the aircraft started to veer to the right by applying left rudder instead of differential braking to realign the aircraft to the runway.
The aircraft in 2008 (Source www.planespotters.net © Björn Düwel)
Several safety recommendations were also made;
For the PF a. To anticipate the effect of cross tailwind, especially during landing roll (weather vaning to the wind). b. To exercise the use of differential braking particularly on speed below 60 knots to control the swerve during the landing roll.
For the operator's maintenance provider a. To ensure that tires being installed in the aircraft landing gears are all identical and in acceptable conditions. b. To include a functionality test of the CVR before the first flight of each day as part of an approved aircraft checklist and should include listening to the signals on each channel to verify that the audio recorder is properly working. c. To perform periodic maintenance checks of the CVR as part of an approved maintenance check of the aircraft. The periodic maintenance check of the CVR should include an audio test followed by a download and review of each channel of recorded audio. The downloaded recording should be checked for overall audio quality, CVR functionality, and intelligibility.
After being recovered from the grass, the aircraft was inspected, minor damage was found, the aircraft was repaired and released to service. A summary of the investigation report, on which this blog is based, is available for the readers' reference by clicking on the .pdf file below;