Narrative:

I was instructor providing familiarization training to a fully qualified pilot (he was PIC) on new turbo cessna 182. Aircraft had just finished 50-hour break-in period and this was first flight with reduced power settings and training maneuvers (touch and go's etc.). During first portion of flight [we] experimented with different power settings to verify performance with pilot operating handbook performance section. Aircraft engine ran smooth; except during leaning when slight roughness noted. This was thought to be normal engine roughness due to overleaning of engine. When mixture was advanced slightly roughness ended.approaching the traffic pattern for landing practice; the engine operated normally at a lean power setting. On base turn the mixture was enriched and prop control set full forward; approach and landing normal. During the power-up for the touch and go; all appeared normal at first. As aircraft lifted-off and passing 30 ft AGL; the engine began running rough. Distance left on runway was too short to abort takeoff; terrain at end of runway not suitable for landing (buildings; rocks; trees). Aircraft slowly accelerated to approximately 70 KTS. I (instructor); took control of the aircraft from the PIC who was flying. I began a coordinated 15-20 degree bank for a 270 turn back to airport. Aircraft was slowly accelerated to max lift/drag (left/D) (78-82 KTS); max altitude obtained estimated at 150 AGL. After 270 degree turn aircraft was set up for a tight 90 degree turn to final for a successful landing. During the time period of the event (20-30 seconds); the majority of time was spent surveying for least damaging landing spots in the event of further loss of power. A momentary glance at engine multi-functional display (mfd) indications showed two cylinder egt's off-scale low. Other egt's were midscale (normal to slightly low). No other inflight analysis was done. A ground witness later reported he heard the very rough running engine and noticed black smoke from the aircraft. After landing the aircraft was shut down and towed to hangar. [Engine] cowl was removed and no apparent engine damage or oil leaks noticed. Initial discussion with [licensed] airframe/powerplant (a/P) and inspection authorized (I/a) technician indicated a probable fuel injector problem. That initial conclusion seems reasonable based on off-scale low egt readings and observed black smoke.I believe this aircraft's fuel control is set to deliver a computer determined fuel flow based on manifold pressure (mp); RPM; and mixture setting. If one or more injectors are plugged then the total fuel commanded is still delivered but it is delivered to fewer remaining operating cylinders. This produces an overly rich mixture in the remaining operating cylinders. The aircraft has been impounded [by me] and further maintenance inspections are to be performed next week. My follow-up will include determining if one or more fuel injectors were plugged; and if injectors were plugged; why are they plugged?

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Original NASA ASRS Text

Title: A flight instructor reports that during touch and go's their Cessna 182T aircraft began running rough after lift-off. The Lycoming engine indications showed two cylinder EGT's off-scale low. Questions about fuel not used by plugged injectors actually creating an overly rich mixture for remaining cylinders; have not been answered.

Narrative: I was Instructor providing familiarization training to a fully qualified pilot (he was PIC) on new Turbo Cessna 182. Aircraft had just finished 50-hour break-in period and this was first flight with reduced power settings and training maneuvers (Touch and Go's etc.). During first portion of flight [we] experimented with different power settings to verify performance with Pilot Operating Handbook performance section. Aircraft engine ran smooth; except during leaning when slight roughness noted. This was thought to be normal engine roughness due to overleaning of engine. When mixture was advanced slightly roughness ended.Approaching the traffic pattern for landing practice; the engine operated normally at a lean power setting. On base turn the Mixture was enriched and prop control set full forward; approach and landing normal. During the power-up for the touch and go; all appeared normal at first. As aircraft lifted-off and passing 30 FT AGL; the engine began running rough. Distance left on runway was too short to abort takeoff; terrain at end of runway not suitable for landing (buildings; rocks; trees). Aircraft slowly accelerated to approximately 70 KTS. I (Instructor); took control of the aircraft from the PIC who was flying. I began a coordinated 15-20 degree bank for a 270 turn back to airport. Aircraft was slowly accelerated to max Lift/Drag (L/D) (78-82 KTS); max altitude obtained estimated at 150 AGL. After 270 degree turn aircraft was set up for a tight 90 degree turn to final for a successful landing. During the time period of the event (20-30 seconds); the majority of time was spent surveying for least damaging landing spots in the event of further loss of power. A momentary glance at engine Multi-Functional Display (MFD) indications showed two cylinder EGT's off-scale low. Other EGT's were midscale (normal to slightly low). No other inflight analysis was done. A ground witness later reported he heard the very rough running engine and noticed black smoke from the aircraft. After landing the aircraft was shut down and towed to hangar. [Engine] cowl was removed and no apparent engine damage or oil leaks noticed. Initial discussion with [licensed] Airframe/Powerplant (A/P) and Inspection Authorized (I/A) Technician indicated a probable fuel injector problem. That initial conclusion seems reasonable based on off-scale low EGT readings and observed black smoke.I believe this aircraft's Fuel Control is set to deliver a computer determined fuel flow based on Manifold Pressure (MP); RPM; and Mixture setting. If one or more injectors are plugged then the total fuel commanded is still delivered but it is delivered to fewer remaining operating cylinders. This produces an overly rich mixture in the remaining operating cylinders. The aircraft has been impounded [by me] and further Maintenance Inspections are to be performed next week. My follow-up will include determining if one or more fuel injectors were plugged; and if injectors were plugged; why are they plugged?

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.