Maintenance Airframe; Maintenance Powerplant
Training / Qualification
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Company Policy; Human Factors; Manuals; Procedure
Found in all cargo bays; all smoke detectors had been sprayed with an oily unknown substance and was seen while inspecting the cargo areas of the forward; aft and bulk. Nothing was said about them not working only that they had been sprayed with oily unknown substance and the concern was that this could cover the screens which could compromise the particles from entering the photoelectric sensing chamber.Knowing that with the blockage of particles being able to enter; a fire or excessive heat with oily/dust blocking the labyrinth can cause a delay or total failure of the smoke detectors.This was seen while doing a visual inspection of the cargo bays that all the smoke detectors had spray over them. [Component Maintenance Manual] states how to clean the detector when the external detector requires cleaning. I never said anything about the detector not working but the sign off was an operational test checking if they worked; and the [Component Maintenance Manual] of a GVI (General Visual Inspection) of the smoke detectors which is what was written up in the first place and was of concern. The manufacture states that cleaning or replacement of the smoke detector; nut neither was accomplished with the sign off only a test and a visual of all 29 smoke detectors having nothing on them. The ceilings and walls of all the cargos have an oily substance sprayed on them; with spray also on the nozzles for the discharge extinguishers and ceiling lights as well.                                                                                    So again; my concern is that if the cargo bays are being sprayed with an oily unknown substance and this is covering the screens of the smoke detectors with the use of a optic circuit to detect smoke particles which pass through a mesh screen which has now been covered with an oily spray and not cleaned per Component Maintenance Manual. They might be able to pass a test because they are testing the electrical end of the circuit-- but I'm concerned that the smoke detectors that are using two different wavelengths of light to note smoke particles will not be able to analyze properly with the detectors covered and not being cleaned per the manufacturer's instructions.
Maintenance Technician found smoke detectors in cargo bays covered with oily substance.