# SDR 2026FA0000623

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 5, 2025
- Submitted: August 6, 2026
- Operation: General aviation
- Aircraft: [N306VA](https://openairdocs.org/aircraft/N306VA), registered now
- Make and model: Robsin R44
- Aircraft serial: 30111
- Aircraft time: 48 hours
- Engine: Lyc IO540AE1A5
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Cylinder
- Part number: 05K21745
- Condition: Scored
- Location: Engine
- Part time: 48 hours
- Component: Engine, Lyc
- Component part number: IO540AE1A5
- Stage of operation: IN
- How discovered: V
- Nature of condition: R
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2026FA0000623

## Discrepancy

THIS IS A NEW AIRCRAFT. LESS THAN 50HRS HAD BEEN FLOWN BEFORE WE FOUND ISSUES.  LOGBOOK ENTRY, AIRCRAFT HAD A HARD STARTING CONDITION. FOUND STUCK INTAKE VALVES ON CYLINDERS 2, 4 & 5 WHILE DOING A COLD COMPRESSION CHECK. UPON FURTHER INSPECTION ALL THE EXHAUST VALVES GUIDES WERE FOUND TO HAVE SIMILAR CARBON BUILD UP AS THE INTAKE VALVES. THE CYLINDERS WITH STUCK INTAKE VALVES SHOWED EVIDENCE OF THE VALVE MAKING CONTACT WITH THE PISTON FACE. THE INTAKE VALVES THAT WERE NOT STUCK, JUST AS TIGHT AS THE EXHAUST VALVES. ALL PUSH RODS, ROCKER ARMS & PUSH ROD SOCKETS WERE FOUND TO HAVE SCORING AT THEIR CONTACT SURFACES. REMOVED ALL 6 CYLINDERS AND DAMAGED PARTS AND RETURNED TO LYC FOR INSPECTION. INSTALLED 6 NEW CYLINDER KITS, 12 NEW17F19357 ROCKER ARMS, 6 NEW LW-13790 ROCKER ARM SHAFTS, 12 NEW LW 12892 SHAFT BUTTONS, 12 NEW 15B21319 PUSH ROD SOCKETS AND 12 NEW 15F28835-30 PUSH RODS PER LYC OVERHALL MANUAL. PREFORMED ENG BREAK-IN PROCEDURE PRE LYC SI 1427C. FLT CHECKED OK, NO DEFECTS NOTED. AIRCRAFT PUT ON A OIL ANALYSIS PROGRAM, NO FURTHER DISCREPANCIES NOTED.

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