An Overdue Screen Inspection and an Unidentified Oil Cooler
A Piper PA-28-181 arrives for its annual inspection. The Lycoming O-360-A4M, serial L-31245-36A, shows 1,180 hours since major overhaul. The logbook entry for the oil suction screen and pressure filter inspection required by the applicable engine airworthiness directive is dated 14 months ago at 1,110 hours. The four entries preceding it were spaced at 55 to 65 hour intervals. The AD requires that inspection within 50 hours in service or 12 calendar months, whichever occurs first, and repetitively thereafter at intervals not to exceed 50 hours in service or 12 calendar months. Separately, an STC'd replacement oil cooler is installed, and the AD governing that cooler family establishes applicability by part number; the aircraft records contain no oil cooler part number and no Form 337 for the cooler installation.
1. May you approve the aircraft for return to service at the conclusion of the annual?
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No. The AD's compliance time is 50 hours in service or 12 calendar months, whichever occurs first. The calendar limit is controlling here: 12 months have run, so the current inspection is overdue by roughly two months regardless of the fact that only 70 hours have accumulated since the last one. Hours never extend a calendar limit.
There is a second problem. The prior 55 to 65 hour intervals exceeded the 'not to exceed 50 hours' repetitive requirement, so the aircraft has a history of noncompliance. Those are historical violations you should not paper over; note them factually in your discrepancy list rather than rewriting the past.
What you do: perform the required screen and filter inspection now, record it under Section 43.9 with total time and tach, and document the late compliance accurately. You may not sign the airworthy statement on the annual until every applicable AD is complied with and the current AD status is documented, as Section 91.417(a)(2) requires.
2. How do you resolve the oil cooler question, and what records must exist?
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Because that AD applies by part number rather than by airframe serial number, applicability is determined by what is bolted to the airplane, not by the model. You must establish the installed part number from objective evidence: the cooler data plate, the Form 337 for the STC installation, a parts tag, or physical identification. If you cannot establish the part number, you cannot establish AD compliance, and an unresolved AD applicability question is an unairworthiness item.
If the installed part number falls inside the AD, comply with it and record the method and date of compliance. If it falls outside, record the part number and the basis for non-applicability so the next inspector does not have to re-litigate it.
Also correct the records gap: the STC installation should have a Form 337 and a Section 43.9 entry. Their absence is a recordkeeping defect you note and, where possible, reconstruct from the STC holder's instructions and the physical installation.
3. The owner wants to fly the airplane to a shop 90 miles away that has the parts. What are the legal mechanics?
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He cannot simply fly it. The aircraft is not approved for return to service and is not in compliance with an applicable AD.
The realistic options are: perform the screen inspection locally first, which is a short job and may clear the AD entirely; or have the owner apply to the FAA for a special flight permit under Part 21 for the limited purpose of flying the aircraft to a facility where the work can be done. An Inspection Authorization holder has no authority to issue a special flight permit. A permit will only be issued if the aircraft is capable of safe flight for the purpose and the stated conditions are met, and it comes with operating limitations, typically no passengers and a specified route.
What you should not do is sign a conditional annual, a ferry letter, or a 'will comply at next inspection' entry. Your leverage is the accurate record: an overdue AD, described plainly, is what makes the FAA and the owner take the right action.