Service Difficulty Reports (SDRs) are a critical component of aviation safety oversight, serving as a formal mechanism for identifying, documenting, and analyzing mechanical failures, malfunctions, and defects in aircraft systems and components. Submitted by operators, repair stations, and maintenance personnel, SDRs provide regulators and manufacturers with real-world operational data that can reveal emerging safety trends, recurring issues, or potential design flaws.

Now, TBX users are able to quickly search and locate issues within the SDR database right from our platform, giving you another powerful tool to identify potential issues you are seeing in your shop with actual historical reported data.

For example, just a few years ago, our friends at the Columbus FSDO noticed fleet-wide failures across PC-24s and Citations related to the Williams engine FJ-444A compressor blades, including sequential serial numbers. Operators were calling it FOD damage, but in reality it turned out to be a manufacturing defect. Thanks to proper SDR reporting, this manufacturing mishap was promptly corrected by the OEM.

Within our program, we’ve made it super easy to search for SDR failures or cross check what you might be seeing out in the field. For example, in 2020 the FAA issued an airworthiness directive related to cross-flow cylinder assemblies in Continental Engines (520 and 550 series). Operators were required to perform a visual inspection as per MSB18-08B and/or replace any cylinders with the affected part numbers.

For example, a quick search of the SDR database for “Continental Engines” and the part name “Cylinder Head” reveals 265 entries (here are the most recent):

Just clicking on the first four with cracked cylinder heads reveal questions related to both overhauled cylinders and compliance with AD 2020-16-11 / MSB18-08C. Here are some of the excerpts from the SDR descriptions above:

1. AD 2020-16-11 PREVIOUSLY COMPLIED WITH ON 11/12/24 AT 2158.7 FLIGHT TIME (536.5 SFRM) TO PREVENT CYLINDER CRACKS. SEVEN MONTHS AND 64.5 HOURS LATER, CYLINDER #5 CRACKED AND BROKE FREE WHILE AIRBORNE AT 12,000 FEET APPROXIMATELY 18.5 MILES WEST-NORTHWEST OF MGW (MORGANTOWN, WV) LEADING TO A ROUGH RUNNING ENGINE, LOSS OF SOME ENGINE POWER, AND THAT CYLINDER GOING OFFLINE. (LINK)
2. CRACKS / SEPARATION OF CYLINDER EVEN AFTER COMPLYING WITH AD 2020-16-11 OVER 5 YEARS AGO. (LINK)
3. THIS CYLINDER TOTAL TIME IS UNKNOWN BECAUSE IT WAS AN EXCHANGE OVERHAUL… THE WORK ORDER IT STATES THAT MSB18-08C WAS PREVIOUSLY COMPLIED WITH AND VERIFIED BY INSPECTION. 7/1/2022. THE CYLINDER WAS INSTALLED 7/20/2022 DURING A PREBUY/ANNUAL INSPECTION WHICH FOUND MULTIPLE LOW CYLINDERS. ALL CYLINDERS WERE REMOVED AND REPLACED WITH OVERHAULED CYLINDERS. 4 BEING 658595 P/N AND 2 BEING THE UPDATED NON AD CYLINDER P/N 658815. I DON'T THINK THIS FAILURE WAS CAUSED BY ANY OPERATION ERROR. I BELIEVE IT IS A WEAK DESIGN AND NO MATTER WHAT OVER TIME THESE FAILURES WILL HAPPEN. I ALSO BELIEVE THAT ANY CYLINDER IN A2020-16-11 SHOULDN'T BE ALLOWED TO BE OVERHAULED BECAUSE OF EVENTUAL FAILURE LIKE THIS. (LINK)
4. WHILE APPROACHING INTENDED DESTINATION OF SSI, LEVEL AT 5,000 FEET, THE PLANE STARTED VIBRATING/SHAKING WITH A LOSS OF PERCENT POWER AND MANIFOLD PRESSURE, AMONG OTHER INDICATIONS. CYLINDER #6 EGT WENT OFFLINE, INDICATING A PROBLEM WITH THAT CYLINDER. TURNED AROUND TO CLOSEST AIRPORT FHB AND MADE AN EMERGENCY LANDING. UPON LANDING, DISCOVERED CYLINDER #6 HAD CRACKED AT THE HEAD BETWEEN THE ROCKER BOX COVERS. CYLINDER SERIAL NUMBER IS AC21IB171 BUT UNSURE OF THE PART NUMBER. THIS IS A FACTORY REMANUFACTURED ENGINE SERIAL NUMBER 1042372 FOR WHICH AD2020-16-11 DOES NOT APPEAR APPLICABLE; HOWEVER, AFTER THIS INCIDENT, IT WAS COMPLIED WITH ANYWAY, FOLLOWED IN JUNE 2025 BY ANOTHER CYLINDER (#5) CRACKING IN THE SAME FASHION. (LINK)

We find this  information and level of detail to be HIGHLY VALUABLE to the aviation maintenance community, allowing A&Ps and IAs to cross correlate issues they are finding in their own shop with other reported issues across North America.

It is standard practice for Part 121 and 135 operators to submit SDRs alongside Part 145 repair stations. While Part 43 maintenance and Part 91 operations are generally not required to submit SDRs, it is generally a good practice to do so, helping other operators, mechanics, and the FAA better understand safety issues facing the GA community. If you are interested in submitting a Service Difficulty Report, use this link here.

For additional resources on SDRs, we recommend checking out Transport Canada's SDR Feedback Articles, another great resource to help you stay on top of safety issues facing the GA fleet.

If you are interested in learning how our software tools help thousands of maintainers, operators, and aircraft owners stay legal, safe, and airworthy, try our 10-day free trial here.

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