Incident Details
On 16 April 2015, the crew of a Piaggio P180 Avanti I began a medical transport flight between EPZG and EPWA. During descent in the EPWA TMA, multiple warning flags appeared on the instruments: left EADI with FD warning, left EHSI with HDG1 warning, center MFD with HDG warning, right RMI with a red flag, and right ADI with a red COMPUTER flag. Following QRH 1, NNC 11-14, the crew switched the HDG switch on the EFIS panel from NORM to XSIDE. The warnings then cleared from the left EADI, left EHSI, MFD, and right ADI. The crew continued the flight, vectored for an ILS approach to runway 33 at EPWA, and landed without further issues. The aircraft was grounded and transferred to SOT Warszawa-Okęcie.
On 17 April, maintenance personnel at SOT inspected and cleaned the autopilot and gyro connection systems and performed functional tests, which were successful. The aircraft was returned to service.
On 20 April, after engine start and during the before-taxi checklist, the pilot observed red HDG flags on the ADI, MFD, and RMI 2, along with an FMS message "EFIS#1 SEL HDG FAIL". The aircraft was shut down and grounded again. Technical staff at SOT Warszawa-Okęcie installed a new primary directional gyro platform (Primary DGS Directional Gyro) and verified system operation. After this corrective action, the malfunction did not recur.
Investigation
The investigation was supervised by Andrzej Pussak. The examining entity was the operator. No investigation team was assigned. The final report was issued on 27 July 2015. No safety recommendations were made.
Cause
The cause of the malfunction was damage to the primary directional gyro platform of the heading indication system.
Preventive Actions
Operational and technical personnel of the air ambulance operator were briefed on the event.