Flight Crew Air Transport Pilot (ATP)
Other / Unknown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Manuals; Procedure; Company Policy
Person X informed me that he had performed a 'maintenance only' test on each of the lavatory hot water systems and determined that all were malfunctioned. When I inquired further as to how he determined the operational status of the water system he explained to me a mechanic had shown him how to initiate a self test on each lav by opening the panel below the sink and turning some switches; then look for a light [to] illuminate. After conferencing with dispatch and maintenance control we were all in agreement that an illegal and unauthorized tampering of each lav's electrical component had occurred; and each had to be inspected by maintenance to confirm switches and breakers etc were in the correct position. A log book entry was made.Person X performed an illegal and unauthorized test of the lavatory hot water system. I attempted to explain to him the breach of safety that had occurred. I do not believe I was able to convey a satisfactory answer to him on why he should discontinue this practice.   I do not believe this practice is wide spread. I do believe a conference with his immediate supervisor is appropriate.
An air carrier Mechanic reported non-maintenance personnel performed a 'maintenance only' test on each of the lavatory hot water systems and determined that all were malfunctioned.