# NTSB LAX94LA220: Robinson R22-B, N140PH, Stockton, CA, May 19, 1994 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 19, 1994, 07:20 local (14:20 UTC) - Place: Stockton, CA - Coordinates: 37.899414, -121.400543 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.8994&lon=-121.4005&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report December 19, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28741 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA220 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28741/pdf - Page: https://openairdocs.org/ntsb/LAX94LA220 ## Probable cause (aircraft 2) A FAILURE OF THE PILOT-IN-COMMAND OF A LANDING HELICOPTER TO MAINTAIN SUFFICIENT CLEARANCE FROM A SECOND HELICOPTER. ## Probable cause (aircraft 1) THE FAILURE OF THE PILOT-IN-COMMAND OF THE LANDING HELICOPTER TO MAINTAIN SUFFICIENT CLEARANCE FROM A SECOND HELICOPTER. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Collision between aircraft (other than midair), standing - idling rotors - object - aircraft parked/standing - clearance - not maintained, pilot of other aircraft (cause) - Collision between aircraft (other than midair), standing - engine(s) operating - object - aircraft parked/standing - clearance - not maintained, pilot in command (cause) ## Analysis (aircraft 2) THE HELICOPTER WAS BEING UTILIZED TO DRY CHERRY TREES IN A LOCAL ORCHARD AND LANDED FOR FUEL AT A PRIVATE AIRSTRIP. THE PILOT HAD REDUCED COLLECTIVE PITCH TO ZERO AND THE ROTOR BLADES WERE STILL TURNING AT FLIGHT IDLE. A SISTER HELICOPTER FROM THE SAME OPERATOR LANDED TO THE RIGHT OF THE IDLING HELICOPTER TO REFUEL. WHEN THE PILOT OF THE SECOND HELICOPTER REDUCED COLLECTIVE PITCH TO ZERO, THE ROTOR BLADES MESHED WITH THOSE OF THE FIRST HELICOPTER. ## Analysis (aircraft 1) THE HELICOPTER WAS BEING UTILIZED TO DRY CHERRY TREES IN A LOCAL ORCHARD AND LANDED FOR FUEL AT A PRIVATE AIRSTRIP. THE PILOT HAD REDUCED COLLECTIVE PITCH TO ZERO AND THE ROTOR BLADES WERE STILL TURNING AT FLIGHT IDLE. A SISTER HELICOPTER FROM THE SAME OPERATOR LANDED TO THE RIGHT OF THE IDLING HELICOPTER TO REFUEL. WHEN THE PILOT OF THE SECOND HELICOPTER REDUCED COLLECTIVE PITCH TO ZERO, THE ROTOR BLADES MESHED WITH THOSE OF THE FIRST HELICOPTER. ## Factual narrative (aircraft 2) On May 19, 1994, about 0720 hours Pacific daylight time, a Robinson R22-B helicopter, N140PH, collided with a second Robinson R22-B, N2314Z, while on the ground at a private airstrip, about 10 miles north of Stockton, California. The two helicopters were being operated as a visual flight rules (VFR) flight to dry cherry trees in the local area when the accident occurred. The helicopters, operated by Sunrise Helicopters Inc., Stockton, California, both received substantial damage. The pilot of N140PH, a certificated commercial pilot, received minor injuries. The pilot of N2314Z, also a certificated commercial pilot, was not injured. Visual meteorological conditions prevailed. The flight originated at Stockton Metropolitan Airport, about 0540 hours. The pilots reported that after terminating the tree drying operation over a local orchard, both aircraft proceeded to Wallom Field, a private airstrip, to refuel. The pilot of N140PH landed near the refueling point and had reduced the engine power to idle. The rotor blades were still turning. The pilot of N2314Z landed to the right side of the first aircraft. After the landing gear skids had touched down, the pilot lowered the collective pitch control to full down. As the second helicopter's rotor blades reached flat pitch, they meshed with those of N140PH. The resulting action caused both helicopters to pivot on the ground. Both aircraft received damage to the main rotor blades, mast and transmission, and tail boom. ## Factual narrative (aircraft 1) On May 19, 1994, about 0720 hours Pacific daylight time, a Robinson R22-B helicopter, N140PH, collided with a second Robinson R22-B, N2314Z, while on the ground at a private airstrip, about 10 miles north of Stockton, California. The two helicopters were being operated as a visual flight rules (VFR) flight to dry cherry trees in the local area when the accident occurred. The helicopters, operated by Sunrise Helicopters Inc., Stockton, California, both received substantial damage. The pilot of N140PH, a certificated commercial pilot, received minor injuries. The pilot of N2314Z, also a certificated commercial pilot, was not injured. Visual meteorological conditions prevailed. The flight originated at Stockton Metropolitan Airport, about 0540 hours. The pilots reported that after terminating the tree drying operation over a local orchard, both aircraft proceeded to Wallom Field, a private airstrip, to refuel. The pilot of N140PH landed near the refueling point and had reduced the engine power to idle. The rotor blades were still turning. The pilot of N2314Z landed to the right side of the first aircraft. After the landing gear skids had touched down, the pilot lowered the collective pitch control to full down. As the second helicopter's rotor blades reached flat pitch, they meshed with those of N140PH. Both helicopters pivoted on the ground and both aircraft received damage to the main rotor blades, mast and transmission, and tail boom. ## Aircraft 1 - Registration: [N140PH](https://openairdocs.org/deregistered/N140PH-1998-11-05), registration cancelled 1998-11-05, S/N 1408 (OpenAirDocs) - Reported make and model: ROBINSON R22-B - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Category: Helicopter - Serial number: 1408 - Airframe hours: 2809 - Engines: LYCOMING O-320-B2C 160 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Operator: David L. Heath, doing business as Sunrise Helicopters - Registered owner: David L. Heath - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 12, 1995, 23 hours before - Airport: Wallom Field ## Aircraft 2 - Registration: [N2314Z](https://openairdocs.org/deregistered/N2314Z-2018-01-11), registration cancelled 2018-01-11, S/N 1995, built 1991 (OpenAirDocs) - Reported make and model: ROBINSON R22-B - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 1995 - Airframe hours: 1990 - Engines: LYCOMING O-320-B2C 160 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Operator: David L. Heath, doing business as Sunrise Helicopters - Registered owner: David L. Heath - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, March 22, 1994, 28 hours before - Departed: SCK - Destination: SCK - Airport: Wallom Field ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N140PH; age 37; commercial; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 1,165 total, 1,162 in this make and model, 1,000 as pilot in command, 100 in the last 90 days, 30 in the last 30 days, 6 in the last 24 hours - Pilot, aircraft N2314Z; age 56; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 3,059 total, 1,636 in this make and model, 2,778 as pilot in command, 29 in the last 90 days, 10 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 10 knots - Visibility: 20 statute miles - Lowest ceiling: 4,000 ft overcast - Temperature: 54 °F, dew point 46 °F - Altimeter: 30.00 inHg - Observed at: SCK, 10 nm away ## FAA reports on this event (2) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19940519011752A](https://openairdocs.org/incident/19940519011752A), May 19, 1994: Robsin R22BETA, Stockton, CA, Substantial damage. Drying cherry trees. Landed refuel. Sister plane landed at right side. Rotors meshed with each other. - [Accident 19940519011751A](https://openairdocs.org/incident/19940519011751A), May 19, 1994: Robsin R22BETA, Stockton, CA, Substantial damage. Hovering drying cherry trees. Landed for fuel sister helicopter landed next to aircraft and rotor blades meshed. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.