# NTSB LAX02LA213: Robinson R22 Beta, N4072T, Chatsworth, CA, July 2, 2002 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: July 2, 2002, 14:45 local (21:45 UTC) - Place: Chatsworth, CA - Coordinates: 34.280834, -118.609558 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.2808&lon=-118.6096&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report June 30, 2004 - Report: Approved by Office Director - Parties: FAA-Van Nuys FSDO, Robinson Helicopter Company, FAA (Los Angeles ACO) - NTSB case key (mKey): 55117 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX02LA213 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55117/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=55117 - Page: https://openairdocs.org/ntsb/LAX02LA213 ## Probable cause The pilot's inadequate flare resulting in rotor blade contact with the ground. Contributing factors were the high altitude and the airframe vibration for an undetermined reason. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, emergency descent/landing - weather condition - high density altitude (contributing factor) - airframe - vibration (contributing factor) - Loss of control - in flight, emergency landing - precautionary landing - performed, pilot in command (cause) - On ground/water encounter with terrain/water, emergency landing - flare - inadequate, pilot in command ## Analysis The 2,155-hour pilot reported that the helicopter developed an abnormal vibration while en-route to a local practice area. The pilot added that he became concerned about the unusual vibration and elected to land the helicopter as soon as possible to investigate the source of the vibration. The pilot executed a power-on approach to a terraced paved area located to the right of his intended course. While on the approach on a northerly heading, as the pilot was flaring the helicopter for a landing, control was lost after the main rotor blades came in contact with the terraced terrain to his right-front. The pilot stated that the engine was performing "normally" and he did not experience a loss of engine power. He added that at the time of the accident, the winds at the accident site were from the south at an estimated 10 to 13 knots. On June 25, 2002, the Robinson Helicopter Company issued an R22 Safety Alert Letter dealing with unusual vibrations and the possibility of a main rotor blade crack. The letter states that "IF MAIN ROTOR VIBRATION INCREASES RAPIDLY OR BECOMES SEVERE DURING FLIGHT, LAND IMMEDIATELY." The pilot recalled receiving this letter three days prior to the accident and indicated this as the reason for his landing attempt. Both tail rotor blades were broken off about 3 ½ inches from their outboard mount points with severe leading edge damage to both blades. One main rotor blade was bent aft and up from its normal position leaving the trailing edge buckled. The other main rotor blade was bent aft and down from its normal position leaving the trailing edge buckled. Small cracks were observed on both main rotor blades near the root fitting and spar cover area. Due to the observed cracks in the main rotor blade root area, the sealant was removed from both blades and they were subjected to a dye penetrate inspection per Robinson Helicopter Company Service Letter 21A. No indications of cracks in the root fitting material of both blades were found. ## Factual narrative On July 02, 2002, at 1445 Pacific Daylight Time (PDT), a Robinson R22 BETA helicopter, N4072T, was substantially damaged following a loss of control during a precautionary landing near Chatsworth, California. The private pilot and passenger sustained minor injuries. The helicopter was owned by the Dragonfly Corporation of Dover, Delaware, and was being operated by Group 3 Aviation of Van Nuys, California. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 flight for which no flight plan was filed. The local flight originated from the Van Nuys Airport at 1420 PDT. The pilot reported that the helicopter developed an abnormal vibration while en-route to a local practice area. The pilot added that he became concerned about the unusual vibration and elected to land the helicopter as soon as possible to investigate the source of the vibration. The pilot executed a power-on approach to a terraced paved area located to the right of his intended course. While on the approach on a northerly heading, as the pilot was flaring the helicopter for a landing, control was lost after the main rotor blades came in contact with the terraced terrain to his right-front. The pilot stated that the engine was performing "normally" and he did not experience a loss of engine power. He added that at the time of the accident, the winds at the accident site were from the south at an estimated 10 to 13 knots. The helicopter came to rest on its left side. The pilot, who was occupying the right seat, exited the helicopter unassisted, and then assisted the injured passenger in exiting the helicopter. There was no fire. There were no reported eyewitnesses to the accident. The pilot summoned for help with his cellular phone. The pilot was issued a private pilot certificate on June 19, 1999. At the time of the accident, the pilot held a single-engine land, single-engine sea, multi-engine land, instrument airplane and helicopter rating. Per the logbook, the pilot had accumulated a total of 2,155.7 flight hours, 452.9 hours of which were in a helicopter. In the last 90 days the pilot had accumulated a total of 24.9 flight hours, 6.1 hours of which were in a helicopter. The pilot's second-class medical certificate issued on January 3, 2002 listed the restriction that he must wear corrective lenses. The Robinson model R22 BETA helicopter (S/N 1747) has a two-bladed main rotor, a two-bladed tail rotor and is powered by a single Lycoming O-320-B2C reciprocating engine (S/N L-14470-39A) rated at 160 horsepower. A review of the maintenance records revealed that the helicopter underwent its most recent 100-hour inspection on May 13, 2002, at a total airframe time of 5,743.2 hours. At the time of the accident, the engine had accumulated 8,699.5 hours since new, 689.1 hours since the last overhaul and 87.2 hours since the last inspection. No evidence of uncorrected maintenance discrepancies was noted in the records. On June 25, 2002, the Robinson Helicopter Company issued an R22 Safety Alert Letter dealing with unusual vibrations and the possibility of a main rotor blade crack. The letter states that "IF MAIN ROTOR VIBRATION INCREASES RAPIDLY OR BECOMES SEVERE DURING FLIGHT, LAND IMMEDIATELY." The pilot recalled receiving this letter three days prior to the accident and indicated this as the reason for his landing attempt. At 1451 PDT, the Van Nuys automated surface observing system (ASOS) at the Van Nuys airport, reported the wind 130 degrees at 7 knots, few clouds at 2,300 feet AGL, 10 miles visibility, temperature 90 degrees Fahrenheit, dew point 41 degrees Fahrenheit and altimeter 29.96 inches of Mercury. The density altitude was calculated by the IIC at 5,685 feet. The helicopter wreckage was located near the ridge top parking lot where the pilot was attempting to land at about 3,000 feet MSL. The aircraft came to rest on its left side on a ledge about 15 feet wide about 10 feet below the parking lot. The wreckage was recovered and moved to the Robinson Helicopter Company facility in Torrance, California, for a detailed examination. The engine had minor impact damage and was rotated using the fanwheel assembly. A thumb compression check revealed compression in all four cylinders and ignition spark was verified at all four cylinders from both magnetos. The main rotor flight controls were separated in four places but no evidence of pre impact failure was found. The tail rotor control system was intact. The driveline to the main and tail rotors was intact. Both the main rotor and tail rotor gearboxes were intact and rotated freely. Both tail rotor blades were broken off about 3 ½ inches from their outboard mount points with severe leading edge damage to both blades. One main rotor blade was bent aft and up from its normal position leaving the trailing edge buckled. The other main rotor blade was bent aft and down from its normal position leaving the trailing edge buckled. Small cracks were observed on both main rotor blades near the root fitting and spar cover area. Due to the observed cracks in the main rotor blade root area, the sealant was removed from both blades and they were subjected to a dye penetrate inspection per Robinson Helicopter Company Service Letter 21A. No indications of cracks in the root fitting material of both blades were found. The wreckage was released to the owner's representative upon completion of the investigation. ## Aircraft - Registration: [N4072T](https://openairdocs.org/deregistered/N4072T-2003-09-19), registration cancelled 2003-09-19, S/N 1747, built 1991 (OpenAirDocs) - Reported make and model: Robinson R22 BETA - 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: 1747 - Airframe hours: 5743 - Engines: Lycoming O-320-B2C 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Group 3 Aviation - Registered owner: Dragon Fly Corporation - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 13, 2002, 87 hours before - Departed: VNY, Van Nuys, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; injuries: minor; private; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review December 26, 2001; seat: right; flight hours: 2,156 total, 1,670 as pilot in command, 25 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 41 °F - Altimeter: 29.95 inHg - Observed at: VNY, 20 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20020702013979A](https://openairdocs.org/incident/20020702013979A), Jul 2, 2002: Robsin R22BETA, Chatsworth, CA, Substantial damage. (.19) On July 02, 2002, at 1445 pacific daylight time, a Robinson R22 beta helicopter, N4072T, was substantially damaged following a loss of control during a… ## Other investigations on N4072T (2) 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. - [NTSB LAX00LA079](https://openairdocs.org/ntsb/LAX00LA079), Jan 22, 2000: Robinson R22B (N4072T), Piru, CA, substantial damage. Probable cause: Failure of the pilot to maintain control after encountering a dynamic rollover. - [NTSB LAX93LA147](https://openairdocs.org/ntsb/LAX93LA147), Mar 12, 1993: Robinson R-22 Beta (N4072T), Folsom, CA, substantial damage. Probable cause: THE STUDENT PILOT'S EXCESSIVE RATE OF DESCENT DURING A APPROACH FOR LANDING, IMPROPER REMEDIAL ACTION TO ARREST THE RATE OF DESCENT, AND A FAILURE TO MAINTAIN PROPER MAIN ROTOR RPM. THE STUDENT… ## Docket (5 files) The files NTSB released with the investigation on April 26, 2004, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=55117. 737 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 329 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40460422&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Manufacturer Accident Report (item 2, .PDF, 249 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40460423&FileExtension=.PDF&FileName=Manufacturer%20Accident%20Report-Master.PDF - Manufacturer safety alert. (item 3, .PDF, 25 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40210613&FileExtension=.PDF&FileName=Manufacturer%20safety%20alert.-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 4, .PDF, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40460424&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 5, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40460425&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Master.PDF 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.