History of Flight
The crew operated a Royal Mail contract between Aberdeen and the Shetland Islands. On 5 September 1999, they flew LN-PBB from Stauning, Denmark to Aberdeen. The next morning at about 0540 hrs, they prepared the aircraft. Mail weighing 1,196 kg was loaded under the commander's supervision. Weather at Sumburgh was reported as poor but expected to improve; Kirkwall was clear as a diversion option.
The aircraft departed Aberdeen at 0640 hrs with the commander as handling pilot. About halfway to Sumburgh, ATC advised the latest weather indicated a landing was not possible. The commander continued toward Sumburgh until a preceding aircraft diverted to Aberdeen, then decided to divert to Kirkwall, landing uneventfully at 0807 hrs.
At Kirkwall, the crew refueled to match the departure fuel load (1,200 lb) and waited for Sumburgh weather to improve. At about 0930 hrs, Kirkwall ATC advised improvement, and the aircraft departed at 0950 hrs with the co-pilot as handling pilot. Cruise was at FL 70. The approach and landing were uneventful until final approach.
ATIS at 1020 hrs reported: wind 340°/07 kt, visibility 9,000 m in rain, cloud few at 300 ft, scattered at 1,000 ft, broken at 1,600 ft, temperature 12°C, dew point 12°C, tempo cloud broken 1,500 ft, wet runway. The crew descended to 2,000 ft amsl and intercepted the ILS from a heading of 300°. The commander noted the co-pilot had difficulty maintaining localiser and glide slope. The co-pilot was unsure of cloud-break height; the commander estimated 500 ft agl. The co-pilot considered the aircraft slightly high and fast; the commander estimated airspeed at 140 kt when visual with the runway. ATC gave three wind reports: 010°/11 kt, 010°/11 kt, 010°/10 kt (two-minute mean surface winds).
Crossing the runway threshold, the co-pilot called out excessive speed and that "it wasn't going to work." The commander, concentrating on the runway, did not respond. Touchdown was approximately halfway down Runway 27. The co-pilot noted a bounce before a second touchdown; neither pilot recalled touchdown speed. Both pilots applied full braking with little effect. As the aircraft approached the runway end, the commander took control and applied full power to clear concrete blocks off the end (a sea defence). The aircraft yawed left, left the runway, crossed grass and a public road, and came to rest on the concrete blocks.
ATC and RFFS response was prompt and effective.
Engineering Investigation
Runway examination could not determine the first touchdown point or confirm a bounce. No evidence of aquaplaning on the runway. About 140 m from the runway end, left of centreline, heavy braking marks from the right main landing gear were visible; no similar marks from the left main gear. Heavy braking continued for about 110 m while the aircraft veered left. Braking marks disappeared near the Runway 09 threshold marks. The aircraft continued 30 m, left the tarmac onto grass, with wheel marks indicating all three gears in contact, yawed left, no apparent braking. It crossed a public road into a second grassy area with no nose gear contact or braking evidence. After crossing about 25 m of tarmac and a concrete sea wall (level with tarmac), all three tyres left marks with aquaplaning on the two main gear tyres. The aircraft departed the sea wall and impacted concrete blocks (approx. 2 m square), halting rapidly. Forward fuselage was below high water mark; airport authority removed wreckage before AAIB arrival. Total distance from first heavy braking mark to final resting place was approximately 275 m.
Wreckage examination showed impact at about 50 kt, high power on the propeller, blades in positive pitch, wing flaps retracted. Forward lower fuselage severely damaged, disrupting flight control and landing gear hydraulic systems, but all systems were intact and functioning before impact. Main gear wheels and brakes were serviceable; tyre damage consistent with ground marks.
Eyewitnesses
The air traffic controller estimated the aircraft landed at the Runway 15/33 intersection (approx. 300 m from Runway 09 threshold), bounced, then touched down again on the touchdown zone markings for Runway 09 (approx. 170 m from threshold). Other witnesses at traffic lights near the Runway 09 threshold (north side) had an uninterrupted view of the latter half of Runway 27; they considered the aircraft landed close to the Runway 15/33 intersection. A video camera at the southern traffic lights recorded the aircraft passing the threshold with all three landing gears on the ground.
Weather Information
Before departure from Aberdeen, crew obtained weather: Aberdeen METAR: no cloud below 3,500 ft. Sumburgh METAR at 0450 hrs: wind 180°/11 kt, visibility 3,000 m in rain, cloud broken at 200 ft, temperature 13°C, dew point 13°C. Kirkwall METAR: wind 350°/10 kt, visibility +10 km in rain, cloud few at 300 ft, broken at 500 ft, temperature 13°C, dew point 12°C. No TAF for Sumburgh. Kirkwall TAF from 0600-1300 hrs: 270°/10 kt, visibility +10 km, cloud few at 1,500 ft, scattered at 2,500 ft, broken at 4,000 ft; TEMPO 7,000 m rain; PROB 30 TEMPO 4,000 m rain, broken at 700 ft; becoming 340°/10 kt between 0600 and 0900.
At Kirkwall, crew received Sumburgh METAR at 0920 hrs: wind 330°/10 kt, visibility 4,000 m rain, cloud few 300 ft, scattered 1,200 ft, broken 2,000 ft. Sumburgh TAF issued 0845 hrs, valid 1000-1900 hrs: 350°/10 kt, visibility 7,000 m rain, scattered 300 ft, broken 500 ft; TEMPO visibility 1,000 m, few 100 ft, broken 200 ft; PROB 30 TEMPO visibility +10 km, scattered 700 ft, broken 1,500 ft. The air traffic services assistant at Sumburgh Tower took a weather observation immediately after accident: similar to ATIS at 1020 hrs: wind 340°/7 kt, visibility 9,000 m moderate rain, cloud few 300 ft, scattered 1,000 ft, broken 1,400 ft, temperature/dew point 12°C, QNH 1016 Mb.
Airport Information
Runway 27 at Sumburgh has a Landing Distance Available of 1,093 m (3,586 ft). ILS flight inspection on 17-18 June 1999 met standards; ground inspection after accident showed full serviceability. Three-degree PAPIs located 198 m from the displaced threshold of Runway 27; all runway lights including PAPIs were on. PAPI angles were checked and confirmed accurate post-accident; the crew could not recall seeing the PAPIs. Runway condition (Mu readings) checked on 2 February 1999 varied between 0.81 and 0.90. A further inspection followed the accident.