MD-83
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Human Factors; Aircraft; Procedure
During my preflight I noticed that the longitudinal trim pointer tip was missing. The longitudinal and aileron trim pointer tips on the MD-80 are tritium-gas filled capsules. Tritium is a radioactive gas that emits electrons while it decays. Those electrons then excite the gas-filled capsule so that it glows as a self-powered gas even in the absence of any direct light source. It is designed that way so that the pilots would be able to trim the airplane in the event of a complete power failure in darkness. Well; the longitudinal trim pointer was missing and Maintenance (MX) signed off the logbook saying that according to McDonnell Douglas Service Bulletin DC-9-27-311 the pointer tip was not required anymore. I accepted the airplane; however; having gotten bogus sign-offs before I promised myself to obtain that bulletin and see for myself. I did and unfortunately that service bulletin deals with modifications to the internal jack-screw mechanism there is not one word in the whole bulletin that would give anyone rise to believe that the pointer tips can be missing. I checked the maintenance manual. It actually says that if the pointers are damaged or broken then everybody would have to leave the cockpit as tritium gas is radioactive/toxic and hazmat procedures have to be followed.How do I know that the missing tip is not somewhere lying broken inside the center pedestal? The bulletin gives no relief to fly with missing pointer tips. Why did MX sign off the logbook with a reference that does not address the discrepancy? How are pilots supposed to safeguard against bogus sign-offs if we do not have access to the documentation that is being referenced? The pointer tips are not mentioned in our MEL book? Can I now assume that either they are installed or if missing the airplane is not airworthy? MX needs to be held accountable for their actions. Bogus sign-offs just to get the airplane off the gate is a no-no. I am extremely disappointed that this happened again.
MD-83 Captain reported a missing longitudinal trip pointer tip. The trim pointer tips are tritium-gas filled capsules. Reporter stated tritium gas is radioactive/toxic and hazmat procedures have to be followed if they are damaged.