History of the Flight
On 23 September 2009, a Dornier 328-100, registration D-CIRT, was being repositioned from Dundee, Fife, to Oberpfaffenhofen, Germany, under a Permit to Fly. The aircraft had not been in regular use for nearly two years and was being prepared for sale. The two pilots, native Russian speakers employed by a German company contracted by the aircraft owners, had arrived in Dundee the previous evening. After an extensive pre-flight inspection, including an external check where the commander noted both engines' oil levels were just below full, and a ground run, the crew declared readiness at approximately 1330 hrs. Weather conditions were good with scattered clouds at 3,000 ft and a strong south-westerly wind.
Takeoff from Runway 27 commenced at 1406 hrs. Shortly after becoming airborne, an amber caution light illuminated briefly. At 1,500 ft, the aircraft accelerated to clean speed, flaps were retracted, and climb power set. Passing 3,000 ft, a right-hand engine alternator caption illuminated along with EICAS messages. While the crew addressed this, the commander noticed the left engine oil pressure fluctuating. The red left engine oil pressure warning then illuminated with an audio alert. The crew levelled at FL60 and declared an emergency with Leuchars ATC.
While receiving vectors back to Dundee, the right engine oil pressure began to fluctuate. The commander considered shutting down the left engine but halted the drill when the right engine pressure varied. The crew requested vectors to the nearest suitable airfield. They sighted an airfield, which they believed was Dundee, but ATC identified it as RAF Leuchars. The crew initially declined to land there, but later positioned for Runway 28 at Leuchars. ATC cleared them to land, and D-CIRT landed safely at 1418 hrs. The crew realized after landing that they were at Leuchars, an airfield not in their FMC database and for which they had no approach plates.
Maintenance History
The aircraft previously operated by City Star Airlines, which ceased trading in January 2008. It was then stored at Aberdeen and later purchased by an asset management company, who made it serviceable and flew it to Dundee in December 2008 for storage. While at Dundee, maintenance followed the manufacturer's storage programme, including routine low-power engine runs. In September 2009, a package of work was carried out to allow a ferry flight, including rectification of defects and power assurance runs. The Luftfahrt Bundesamt (LBA) issued an EASA Permit to Fly after review.
Engineering Investigation
After landing, no external oil leaks were observed, but the left engine had lost approximately seven quarts of oil and the right engine about four quarts. Examination revealed that in both engines, the air-switching valve had seized due to corrosion, causing the oil system to over-pressurize and vent oil overboard. The aircraft's 25-hour FDR and 2-hour CVR were removed for analysis. The CVR recording did not include the incident as it had been overwritten during post-incident engine tests. The FDR data showed multiple oil pressure below-limit conditions recorded by the maintenance computer during the flight.