The Squawk Sheet

✦   Preflight Brief

Fall flying is the best flying. Fall maintenance is the most honest flying.

September marks a shift. The calendar changes, temperatures drop, daylight contracts, and suddenly the maintenance schedule that was deferrable all summer becomes non-negotiable. This month the FAA published a critical AD on a single, thin-walled component found in thousands of Lycoming engines. If your aircraft is affected, this demands action before the next flight.

But September brings a second threat that gets overlooked: carbon monoxide. As cabin heat comes on and windows close against cooling air, this silent killer — colorless, odorless, lethal — becomes a real presence. Most owners have never considered it. Most mechanics rush through the check. This month we change that conversation entirely.

Plus: we're offering a comprehensive fall inspection that combines two critical systems into a single, affordable appointment. This is not coincidence. Read on.

On August 28, 2026, the FAA issued Airworthiness Directive 2026-17-10, requiring inspection and replacement of thin-walled piston pins P/N LW-13445 installed in Lycoming O-235, O-540, and IO-540 engines. The directive applies to 957 affected engines currently on the U.S. registry and affects a broad cross-section of single-engine Cessnas, Pipers, Mooneys, Beechcraft, and multi-engine aircraft. The root cause: manufacturing defects introduced during a supplier's honing and tooling process change between January 7, 2021, and December 15, 2025. The piston pin — a thin-walled steel cylinder approximately .84 inches in diameter (roughly the size of a nickel) — connects the connecting rod to the piston and must withstand combustion pressures and cylinder loads with precision. Microcracks and inclusions in affected pins can lead to pin failure, loss of compression, and uncontrolled engine shutdown in flight.

Compliance Depends on Your Engine's Table

If your engine serial number falls in Table 2 (manufacturing date January 7, 2021 – March 22, 2023): You may continue to fly your aircraft with the affected piston pin installed. You must replace the pin at your next maintenance event requiring cylinder removal, OR at your next engine overhaul (compliance deadline driven by your maintenance schedule, not an immediate grounding).

If your engine serial number falls in Table 3 (manufacturing date March 23, 2023 – December 15, 2025): If your engine has fewer than 150 hours time in service since the pin was installed, replace the pin within your next 25 hours of operation. If your engine has more than 150 hours time in service, you must complete an oil analysis per Lycoming Service Bulletin 480 before next flight. If the analysis shows no corrective action needed, you have 5 hours to schedule the replacement.

What to do right now: Determine your engine's serial number (it's on your engine data plate, visible during preflight). Cross-reference that serial number against Tables 2 and 3 in SB 667A. You can call Lycoming at +1 (570) 327-7222 or +1 (877) 839-7878 to confirm which table applies. Or call DJS Aviation at 682-420-4677 anytime — we will determine which table your engine falls under, calculate your compliance window, and walk you through exactly what needs to happen next. Contact your A&P or maintenance shop to schedule the replacement according to your compliance window. Contact an Authorized Lycoming Distributor — warranty coverage is available for both parts and labor under Lycoming Engine's Limited Warranty policy. Engines outside the factory warranty period may also qualify for parts reimbursement and labor coverage.

Fall flying is the best flying. Crisp air, clear skies, lower density altitude, and no summer haze. But the transition to autumn brings hazards that most owners only think about when something goes wrong. Two of them kill pilots every year: carburetor icing and carbon monoxide poisoning. Both are invisible. Both are preventable. Both require you to know they exist.

Summer is when aircraft owners fly without thinking. Fall is when the thinking begins — and usually, it comes with regret. The preflight walk-around that sufficed in July — kick the tires, scan for obvious damage, climb in — becomes indefensible in September. Suddenly, systems that seemed fine in August demand attention. The exhaust integrity you did not think about. The battery capacity you took for granted. The alternator you kept meaning to replace. All of it becomes research fuel for 2 a.m. internet searches.

Here is the truth every experienced mechanic knows: the season does not create maintenance urgency. The aircraft was already telling you what it needed. Fall simply makes the consequences impossible to ignore. A cracked exhaust in September was cracked in August — the difference is whether you fly with heat, which turns probability into certainty. A weak battery in October was weak in September. Fall does not invent these problems. It exposes them.

This is why experienced owners treat fall not as a deadline, but as an opportunity. An opportunity to address maintenance that summer carelessness postponed. An opportunity to do it before the calendar turns cold and turns every mechanic's schedule into a war zone. Owners who call in September do not sit in waiting queues in January. They fly through winter without apology. That is the difference.

This September, bring your aircraft in for any maintenance — routine or otherwise — and DJS Aviation will perform two complete heat system inspections at no additional charge. This is not a limited offer or a loss leader. This is us putting our money where our attention goes. Two systems. Zero surprises. Peace of mind before the seasons turn cold.

Why both systems? Because fall flying safety rests entirely on both functioning flawlessly. Carb ice disables the engine mid-descent. Carbon monoxide compromises your judgment before you understand what is happening. Address both in a single appointment and you leave the hangar knowing the two most dangerous systems on your aircraft are ready for every cold-weather hour ahead.

This offer applies to September 2026 only when combined with any other maintenance work. We treat fall inspections as priority. Call now — the September schedule will fill fast.