Date: 201307
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 20
Light: Daylight
Aircraft: Robinson R44
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Landing
Airspace: Class G ZZZ
Second aircraft: Cessna 140
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Other / Unknown
Second reporter function: Single Pilot
Anomaly: Conflict Ground Conflict; Critical; Ground Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Wake Vortex Encounter
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged; Flight Crew Regained Aircraft Control
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: I landed our Robinson RH-44 helicopter on the runway under clear skies with light winds. It is a privately-owned uncontrolled airfield. On CTAF I made the proper radio calls on downwind; base and final legs. Just past the approach end of the runway; I offset to the left over the grass taxiway and radioed clear of the runway. I had transitioned to air taxi; parallel to the runway; and was headed toward the parking area when I felt a slight bump as an aircraft slid by me; from back to front; on the right-hand (runway) side. I proceeded to parking and landed without difficulty; with no change in the helicopter's handling. An A&P Mechanic was present on the field and he inspected the aircraft. No damage was found. He concluded that the bottom of the right skid had been contacted by the other aircraft. I lifted off in a hover while the Mechanic inspected the aircraft. No damage; including either skid was found. The other aircraft; a Cessna 140; sustained a tear in the covering fabric about two feet inboard from the top left wingtip. The tear was the size of a postage stamp; 3/4 by 1 1/2 inches. The pilot said he lost directional control of the aircraft on landing and departed the runway to the left onto the grass. Tire skids marks on the runway showed a locked right brake with the aircraft still turning left. I believe there were two causes for the event. Primarily; the Cessna 140 followed far to close in the landing pattern and should have gone around. There was insufficient lateral clearance on the paved runway and grass taxiway for both of us to safely operate. Second; the Cessna pilot said he lost control of his aircraft on landing roll; with the aircraft turning sharply to the left; in my direction; as he approached the helicopter from behind.


Second narrative: Upon completion of a personal flight the C140 was following an R44 for landing. The R44 was about 1/2 mile ahead of the C140 on final. After the R44 crossed the runway threshold it moved left off the runway and entered into a hover about 8-10 FT off the ground. The R44 was about 50 FT or more left of the runway centerline; off the pavement and hovering over a grass area. The C140 proceeded to land touching down on the pavement about 500 FT before the R44. During roll out; the C140 was unable to stay on the runway centerline and was pulled left. Full right rudder and brake was applied but the C140 continued to be 'pulled' left eventually having the left wing pass under the right skid of the R44. After passing under the R44 the C140 was able to regain control; it proceeded straight and came to a stop about 500 FT past the R44.There was no damage to either aircraft.Post event review determined the C140 right wheel was indeed locked as shown by a skid mark; about 300 FT long; on runway. It was assumed that the rotor vortices caused the C140 to turn (weathervane) left.The C140 pilot should have landed past the R44 to avoid any rotor wash or should have executed a go-around; waiting for the R44 to be fully landed and not in a hover.The landing runway itself was short (2;000 FT) with trees at the end making a (successful) aborted landing questionable. Thus applying full power may have allowed [the pilot] to regain of control but could have also resulted in the inability to fully stop or climbout without coming in contact with trees at the end.


Synopsis: Helicopter pilot reports being bumped on the main skid by a landing C140 as the helicopter is air taxied over the grass to parking. There is no damage to the helicopter and slight damage to the top of the aircraft's wing. The aircraft pilot lost control during the landing roll and departed the runway. The C140 pilot believes the rotor wash caused the loss of control.