Service difficulty report · Cylinder · Robsin R44

Difficulty date
December 5, 2025
Submitted
August 6, 2026
Operation
General aviation
Aircraft
N306VA
Make and model
Robsin R44
Aircraft serial
30111
Aircraft time
48 hours
Engine
Lyc IO540AE1A5
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

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

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.