Incident Description
On 21 February 2012, during climb shortly before reaching cruise altitude, an Embraer E170-100 experienced an illumination of buttons on the lower panels: L/H R/H REV. PANELS ADS IRS WATER DUMP GND PROX TERRAIN INHIBIT, GND PROX INHIBIT G/S, LG WARNING INHIBIT. The captain, after consulting with the operations center, decided to return to the departure airport (EPWA). A similar malfunction had occurred the previous day on the same aircraft.
Maintenance Actions
Following the first occurrence, maintenance replaced three lower panels: WATER DUMP, GND PROX TERR INHIB/EMERG PRK BRK GND PROX G/S INHIB/LG WRN INHIB AND LH/RH REV, in accordance with AMM procedures 31-61-02, 31-17-01, 31-17-02, and 38-11-16. The aircraft was returned to service the next day, 22 February 2012. However, during the subsequent Milan–Warsaw flight, the malfunction recurred. After landing in Warsaw, maintenance swapped the previously replaced panels with panels from another aircraft. As the fault could not be reproduced on the ground, the aircraft was cleared for operation. On 23 February 2012, during a Zurich–Warsaw flight, the issue appeared again. The aircraft was then taken to a hangar, where technicians discovered damage to the insulation of wire bundle W102-00598-22. The insulation was repaired, and the aircraft was returned to service on 24 February 2012. The malfunction did not recur.
Cause
The cause of the incident was damage to the insulation of wire bundle W102-00598-22.