Aircraft and Crew
The aircraft involved was a Cessna 525B CitationJet CJ3, registered as N525L. It was operated by Morgran Management, LLC and owned by Delaware Trust Company. The pilot, an Italian citizen born in 1953, held a Commercial Pilot Licence issued by the FAA. His total flying experience was 5558:36 hours, but he was not willing or able to provide reliable information about his recent flying hours. The aircraft was equipped with a cockpit voice recorder (CVR) but not a flight data recorder (FDR).
Background of the Flight
Strange noises related to the autopilot had been noticed from the control columns during previous operations. The maintenance company decided to carry out a test flight, with the mechanic sitting in the right-hand pilot's seat to identify the noises. However, due to weather delays at Zurich Airport, air traffic control did not permit a test flight. Instead, a flight to Sion and back was planned to test the autopilot. Shortly before departure, the pilot was informed that a colleague (a helicopter pilot) would also be on board, so the mechanic moved to the cabin and the colleague occupied the right-hand seat.
History of the Flight
On 17 August 2018 at 16:51:07 UTC, the pilot received takeoff clearance from runway 28 at Zurich Airport, with instructions to follow the VEBIT 3W standard instrument departure (SID) and climb to 5000 ft QNH. Shortly after takeoff at 16:51:48 UTC, the "autopilot" acoustic warning sounded for the first time, indicating the autopilot had been disengaged. The air traffic control officer (ATCO) instructed the pilot to switch to Zurich Departure frequency 125.95 MHz. The pilot did not confirm immediately; after a repeated instruction, he responded "departure" at 2500 ft.
The pilot attempted to contact departure on 125.95 but received no reply. At 16:52:42 UTC, he queried Zurich Tower about the frequency, and was corrected to 125.95. Meanwhile, the aircraft passed D2.3 KLO and began a left turn of approximately 7 degrees, whereas the SID required a 90-degree left turn to intercept R053 WIL. At 16:52:57 UTC, the aircraft passed the assigned altitude of 5000 ft and continued climbing. The "altitude" warning sounded repeatedly as the aircraft deviated from the selected altitude.
At 16:53:03 UTC, Zurich Departure contacted the pilot, who responded "go ahead". The ATCO cleared the aircraft to climb to FL 120. The pilot acknowledged "climbing 120". At 16:53:19 UTC, the ATCO asked the pilot to report passing altitude; the pilot responded "Passing 5000 climbing for 12". The ATCO later instructed a left turn heading 210, which the pilot acknowledged. However, the pilot was not following the SID, and the ATCO noted that a report would be filed.
Autopilot and Communication Difficulties
Throughout the flight, both "autopilot" and "altitude" warnings sounded repeatedly. At 16:57:10 UTC, when asked if he was proceeding to VEBIT, the pilot stated "Autopilot is u/s I come back". The ATCO instructed a heading of 240 degrees. The pilot then indicated he had an autopilot issue and needed to return to Zurich. The ATCO vectored the aircraft for an ILS approach to runway 14, but the pilot requested a visual approach, which was approved.
During the return, the autopilot warnings continued. At 17:02:28 UTC, the pilot reported "now the autopilot is working". At 17:03:23 UTC, he said "the autopilot is working now, we are able to continue but I prefer a visual". The aircraft subsequently landed safely. No damage to the aircraft or injuries to occupants were reported.
The pilot provided a brief written report but exercised his right to refuse a statement. The accompanying pilot and mechanic provided statements to the investigation. Data from the CVR and air traffic control recordings were used.