What happened
On 1 May 1999, a Fokker F28 Mark 100, registration G-UKFR, was conducting a public transport flight from Amsterdam to Aberdeen. Approximately 40 minutes into the cruise phase, the first officer reported a smell of burning. While the commander initially could not detect the odor, a strong smell of electrical burning became evident once the cabin supervisor entered the flight deck. In response, the commander ordered the flight deck door to be closed and all further communication to be conducted via interphone.
During the incident, the right primary flight display (PFLE) began to fluctuate and display non-standard information. As a safety precaution, the crew deactivated the first officer's PFD, navigation display, and flight management computer. The pilots also donned oxygen masks and deactivated the aircraft's re-circulation fans. The commander, who was the non-handling pilot at the time, declared a PAN call and requested an immediate descent and diversion to Humberside Airport. During the descent, the aircraft experienced several level 2 alerts regarding the flight management computer, loss of map information on the remaining navigation display, and a failure of the flight director.
The crew executed a raw data surveillance radar approach (SRA) to mitigate the risk of total navigation loss. After acquiring the runway visually, the aircraft landed without further incident. No zero fatalities or injuries were reported among the 5 crew members or 73 passengers. Following the landing, the aircraft was shut down and passengers disembarked via standard exits while emergency services monitored the scene.
The investigation
Maintenance personnel examined the aircraft and replaced the faulty right PFD, after which the system operated normally without any further smell of burning. The defective unit was sent to the manufacturer for analysis. The investigation established that a burnt out Random Access Memory (RAM) electronic chip was the source of the failure within the display unit. Following repairs and modifications in line with relevant service bulletins, the component was returned to service. The specific cause of the chip's failure could not be determined.