Commercial Fixed Wing
Maintenance Powerplant; Maintenance Airframe
Workload; Communication Breakdown; Time Pressure
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
Aircraft Aircraft Damaged; General Maintenance Action
Procedure; Aircraft; Company Policy; Human Factors
Aircraft X was in a storage state during preservation maintenance when an engine run was accomplished on both #1 and #2 engines with their main oil tank empty and their respective main accessory gearbox drained of oil as well. This is an event that is unprecedented; I am here to focus on how serious this is in regards to determining serviceability of the subject engine(s). As an experienced lead AMT; I am no stranger to engine overhaul; test cell duties; diagnostic test flights or on-wing engine/taxi runs. I know how violent an engine reacts when it incurs an internal failure while in operation and to summarize the thought process; it's fortunate that many of these failures happen on the ground during maintenance but some unfortunately happen when an aircraft is in service and in flight.Every engine manufacturer designed these engines to operate normally on different phases of flight under different conditions providing that the operator/consumer; observes; adheres to all or any operational instructions provided. In regards to engine oil quantity; our company pre-run checklist; before an engine is even operated; it must contain a minimum of 1X quarts of main oil quantity as displayed in the flight deck. I have no doubt that an engine will still operate normally with lesser quantity if oil pressure and oil temps remain normal and no other abnormal parameters are observed. If an anomaly does happen during an engine operation that's related to oil and or lubrication system; especially those observed readings that can indicate an impending failure or incursion beyond its operating limits; the engine in operation must be stopped immediately. The company has ample resources available to address or troubleshoot these issues in the form of MMs; FIMs; TSMs; etc.; and likewise; all modern aircrafts has built in systems known as recorder mediums such as PCM; DMU; and FLT RCDR that can be downloaded as necessary to provide insight and health assessment to many operating parameters including engines at real time or recorded. With the issue we have; none of the recording mediums downloaded has provided us with any source of readings and or indications that may shed light as to how we can possibly approach and deal with this problem. Here's the issues that I have: These engines were run with no oil in tank and main accessory gearbox oil was drained as well. With the rate of speed that these engines operate even at idle; there are many parts within the scope of the lubrication systems that is dependent on proper oil pressure in order to maintain normal operating temp such as the huge thrust bearings; sideload bearings and other compartment bearings along with the other critical parts like the scavenge and pressure pumps. Common sense will also dictate that with no oil to begin with; these bearings and critical seals have now been exposed to undetermined excessive heat that may have inflicted heat damage and reduce life cycle on other parts. I have thoroughly searched the MM and TSM in hopes to provide me some insight on how to troubleshoot or address this issue and found none. In fact; due to my curiosity; I have checked all the other fleets troubleshooting manuals and was unsuccessful as well. The only fleet that came close to addressing an oil pressure issue involves the CFM engines and that's whenever its engine oil pressure goes below minimum limits that exceeds 30 seconds; the engine is to be replaced. Engines are just not designed to operate with the oil system drained and it's beyond my scope of knowledge and experience to determine serviceability. Unless an engine manufacturer can provide us insight; recommendations or have experienced a similar event and shares us the information and or make known to us what decision that had to be made; we and the Company is in a serious predicament. What we are being asked as part of the maintenance process are these EG callouts that instructs to check MCDs and perform numerous engine runs as to ascertain and prove its serviceability. These engine runs are unfounded and lack merit and frankly speaking; they are very dangerous. They clearly appear experimental; based on assumptions and not ECRA supported. These proving engine runs are best authorized and done in a test cell environment where it is safe and properly managed. In summation; these engines were not run with a low oil qty condition as many may have thought or have been misled to think. One would argue that it still had oil in the form of residuals in the lines and that would be enough to come to a conclusion that all the bearing compartments and other critical areas were not affected or heat damage is not a factor. These types of arguments are foolish and obviously do not share the same mindset as I and that is to operate with a mindset that's geared towards safety; legality and have a high degree of confidence that the right decision is made; without any doubts or reservations. The public views us as an airline of choice and as we transport them around; they expect guaranteed reliability; safety and comfort. In conclusion; the decisions to be made hinges on two different paths. One is to render the engine serviceable after maintenance proving runs that is unfounded; lack merit or support from many technicians and frankly speaking; the engine(s) are damaged goods! The other direction is to follow the only recourse that should have been in the first place. Stop these foolish maintenance practices that may prove dangerous downline and do what's right.
Lead Aircraft Technician reported an aircraft in storage had both engines run with no oil in either the main oil tank or accessory gearbox.