Incident Overview
On September 10, 2013, an Embraer E170-100 was climbing after departure from Gdańsk (EPGD) when, upon passing FL150, the flight crew received a FLAP LO RATE caution and an ADS 1 HTR FAIL warning. In response, the crew decided to return to Warsaw (EPWA). The aircraft landed without further incident and in the proper landing configuration.
Maintenance Actions
After landing, the aircraft was handed over to maintenance. Technicians performed mechanical and electrical rigging adjustments on the flap system in accordance with AMM procedures 27-50-00-820-801A and 27-50-00-820-802A Revision 36. A subsequent operational test per AMM 27-50-00-710-801A Revision 36 confirmed that the flaps functioned normally.
The ADS HTR FAIL warning could not be reproduced during a ground test per AMM 30-31-00-710-801-A. However, on September 13, 2013, during a technical test flight intended to verify the flap repair, the ADS HTR FAIL warning reappeared. To address this, the number 2 Air Data Smart Probe was replaced in accordance with AMM 34-13-01-04 Revision 37.
Findings and Cause
The investigation determined that the incident was caused by a spontaneous misadjustment of the flap system.
Safety Recommendations
No safety recommendations were issued by the investigating body.