On 24 January 2012, a Boeing MB83 being operated by Spanish ACMI operator Swiftair for South African operator Gryphon Airlines on a scheduled passenger flight from Dubai to Kandahar struck the ground in the undershoot area of the landing runway at destination with one wing in day Visual Meteorological Conditions (VMC) before completing a landing on the runway. After clearing the runway, TWR, with service provided by a supervised trainee who had observed the ground impact and corrective action, instructed the aircraft to hold position and shut down the engines to facilitate an Rescue and Fire Fighting Services inspection to check that there was no fuel leak and that the wheels and brakes were apparently undamaged. Nothing untoward was found and the aircraft was permitted to restart engines and taxi in for a normal passenger disembarkation. There were no injuries to the 86 passengers and 5 crew.
An Investigation was carried out by the Spanish investigation agency CIAIAC as the State of the Operator. It was noted that following the accident, the flight crew had made “no effort to preserve the contents of either the cockpit voice or flight data recorders”. As a result the data from the 30 minute Cockpit Voice Recorder (CVR) had been overwritten but fortunately the Flight Data Recorder (FDR) data was still available and was successfully downloaded for use in the Investigation.
The damaged right wing seen from behind (reproduced from the Official Report)
In addition to significant damage to the right wing caused by the ground impact (see the picture above), five runway threshold lights were also destroyed.
It was found that although both pilots had significant experience on the aircraft type they had only re-joined the operation six days prior to the accident flight. Both were familiar with Kandahar, the Captain more so than the First Officer.
It was established that after an uneventful flight from Dubai, Kandahar Control had cleared the aircraft for an Area Navigation Systems (Global Positioning System (GPS)) approach to the 3204 metre long runway 05 (which had an MDA equivalent to just under 400 feet aal - see the IAC below) and provided an appropriate radar heading towards final approach. The crew were aware via Notice To Airmen that the Visual Approach Slope Indicator Systems for runway 05 was out of service. With the First Officer acting as PF, the approach was flown with the AP engaged and commenced in Instrument Meteorological Conditions (IMC). The aircraft remained above the vertical profile and still was so when cloud was exited at approximately 1900 feet aal, The prescribed stabilised approach gate of 1000 feet agl was passed with a recorded rate of descent of 2650 fpm and a recorded airspeed of 192 knots. The operator stabilised approach requirement for maximum speed at and from this point was Reference Speed (Vref) +20 knots (155 knots for the accident approach) and the maximum permitted rate of descent at 1000 feet agl was 1000 fpm. The prescribed go around was not initiated at this gate or even considered subsequently.
The IAC for the Runway 05 approach flown (reproduced from the Official Report)
Shortly after exiting cloud, the runway was sighted and, with the aircraft about to join the vertical profile from above and also to the right of the FAT, the Captain took control. Approaching 500 feet aal, the AP was disconnected. The MDA was reached soon afterwards at a range of 1nm from touchdown but at this point (see the first diagram below) the aircraft was to the right of the extended centreline and still diverging. As lateral correction was attempted, the aircraft began to go below the published vertical profile (see the second diagram below). At about half a mile from the runway threshold, the aircraft had descended to only 13 feet agl. When a 20° roll to the right occurred, the right wing hit the ground in the undershoot area approximately 20 metres before the runway threshold with a vertical acceleration recorded as 1.36g. Thereafter, this wing was dragged along the ground until the aircraft reached the runway, damaging five runway edge lights. At the time of ground impact, the airspeed had dropped 18 knots below the applicable Vref. The Investigation noted that with the A/T in RRTD mode, any attempt to increase pitch results in a decrease in speed since thrust is at flight idle and will not increase.
The estimated track of the aircraft (the lateral deviation shown is indicative only) (reproduced from the Official Report)
It was confirmed that the accident aircraft pilots had both received training in respect of operating into Kandahar which was in accordance with the Company aerodrome classification of Kandahar. However, it was found that the accident aircraft had only European “BRNAV” equipment fitted and thus there could be no operational approval which permitted the RNAV (GPS) approach that was made and the flight crew had not been trained on and authorised to conduct such an approach.
Although most of the approach was made in IMC, the prevailing weather conditions were not considered by the Investigation to have been a material factor influencing the way the approach was flown.
Having noted that any GPWS/TAWS activations would not have been recorded on the FDR, the Investigation did not then seek to establish this from the record contained in the GPWS unit Non Volatile Memory.
It was formally concluded that the likely Cause of the accident was “the failure to observe the company’s operating procedures and not executing a go-around when the approach was clearly not stabilised". It was noted that “moreover, the operator lacked the authorisation (and the crew the training) to carry out the RNAV (GPS) approach manoeuvre that was conducted at RWY 05 of the Kandahar Airport".
It was concluded that a Contributory Factor to the accident outcome was “the inoperable status of the PAPI at runway 05 of the Kandahar Airport, which was thus unable to aid the crew to establish the aircraft on the correct descent slope”.
Four Safety Recommendations were made as a result of the Investigation as follows:
- that Swiftair, S.A., responsible for the operation, generate a procedure intended to ensure that its crews do not carry out unauthorised (and thus unsanctioned) manoeuvres. [REC 50/13]
- that Swiftair, S.A., responsible for the operation, generate a procedure intended to ensure that its crews receive proper training on adherence to operating procedures. [REC 51/13]
- that Spain’s Aviation Safety Agency (AESA) ensure that Swiftair, S.A. crews do not carry out unauthorised (and thus unsanctioned) manoeuvres. [REC 52/13]
- that Spain’s Aviation Safety Agency (AESA) ensure that Swiftair, S.A. crews receive proper training on adherence to operating procedures. [REC 53/13]
The Final Report was approved on 25 September 2013 and subsequently made available in English translation.