# NTSB LAX97LA260: Robinson R22 Beta, N4008D, Chandler, AZ, July 25, 1997 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: July 25, 1997, 15:30 local (22:30 UTC) - Place: Chandler, AZ - Coordinates: 33.240459, -111.779998 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.2405&lon=-111.7800&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report April 10, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 29851 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX97LA260 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29851/pdf - Page: https://openairdocs.org/ntsb/LAX97LA260 ## Probable cause The CFI's failure to recognize and correct for a vortex ring state, and his improper use of the flight controls, which resulted in the loss of control and uncontrolled descent. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, cruise - rotorcraft flight controls - improper use of, pilot in command(cfi) (cause) - settling with power - encountered (contributing factor) - vortex ring state - not identified, pilot in command(cfi) (cause) - remedial action - not performed, pilot in command(cfi) (cause) - In flight collision with terrain/water, descent - uncontrolled ## Analysis The CFI and private pilot were practicing maneuvers at the airport. The CFI stated that the helicopter was suddenly in a nose-low attitude with a high rate of descent. He said he tried to raise the collective to stop the descent rate with no apparent result. The student stated that he began a 30-degree banked turn to the left. He said the instructor felt the turn was 'too lazy' and he took control of the aircraft and proceeded to increase the bank angle to approximately 45 degrees. The aircraft then began to pitch nose down, the collective and cyclic began to shake and vibrate, which he said continued until impact. The student is a private pilot with both single engine land and rotorcraft helicopter ratings. He had approximately 76 hours of fixed wing time and 223 hours in rotorcraft. ## Factual narrative On July 25, 1997, at 1530 hours mountain standard time, a Robinson R-22 Beta, N4008D, collided with the ground following an in-flight loss of control while on the crosswind leg for landing at Chandler, Arizona. The aircraft was destroyed by the ground impact sequence. The flight instructor sustained serious injuries and the dual student sustained minor injuries. The aircraft was being operated as a instructional flight under 14 CFR Part 91 when the accident occurred. The flight originated in Chandler at an undetermined time for a takeoff and landing practice. Visual meteorological conditions prevailed at the time of the accident. The certified flight instructor (CFI) told the Federal Aviation Administration (FAA) that they departed Chandler Municipal Airport between 1500 and 1515. They were en route to Chandler Memorial Airport for pattern work. Once they arrived, he had the student practice steep approaches, hover techniques, autorotations, and normal takeoff procedures. The CFI reported that the aircraft was operating normally. The CFI told the FAA inspector that he instructed the student to "perform a takeoff and climb maneuver, flying runway heading 30, then turn left (20-25 degrees) at 1900' msl." In the turn, the CFI stated he took over the aircraft controls because "Mr. Tabata was not performing the maneuver properly." The CFI told the FAA in his written statement that the "aircraft was loosing altitude. . .he said he tried full up collective and full throttle but the aircraft did not respond and crash landed in the west side of the runway." The CFI reported in his report that the aircraft was "suddenly in a nose-low attitude with a high rate of descent." He said he tried to raise the collective to stop the descent rate with no apparent result. He further stated that there were "numerous dust-devils" around the airport which they had maneuvered around several times. He stated he "believes we encountered one of these dust-devils, thus leading to the accident, and loss of control." The dual student was interviewed by the FAA inspector on July 26, 1997. He told the FAA inspector that he preflighted the helicopter and found no discrepancies to report. He stated that he verified fuel tank quantity, visually, and with the fuel tank indicator; both of which registered full. He stated that this was the first flight of the day for both the aircraft and both pilots. The student stated that after accomplishing the preflight run-up, they departed Chandler Municipal Airport to the west en route to Chandler Memorial Airport. He stated the cruise altitude to Chandler Memorial Airport was 1700 feel msl. He said they entered the traffic pattern at 1700 feet using runway 30 with a left traffic pattern. The student reported that they made one normal approach to runway 30, performed hovering and landing techniques on the runway numbers, performed 360-degree turns, and then proceeded to climb out to traffic pattern altitude and performed one steep approach. Afterwards, they performed two autorotations and two 180-degree autorotations. The student reported that at approximately 1530 he performed a "normal take-off" climbing to 1700 to 1800 feet and "began a 30 degree bank to the left." He stated that the instructor felt the turn was "too lazy" and took control of the aircraft. He said the instructor proceeded to "increase the bank of the aircraft to approximately 45 degrees (to the left)." He further stated that the aircraft then began to pitch nose down, the collective and cyclic began to shake and vibrate, which continued until impact. The student also told the FAA that the aircraft had a nose-up attitude prior to impact. The student holds a private pilot certificate with single engine land and rotorcraft-helicopter ratings. He told the FAA that he had approximately 76 hours of fixed wing time and 233 hours in rotorcraft. He said he arrived in Arizona on July 8, 1997, and began flight training with the operator on July 10, 1997. He was training for a commercial add-on rating in rotorcraft. At the request of the Safety Board, the engine was examined under the supervision of an FAA inspector on August 4, 1997. According to the inspector's report, both the left and right magneto's were operationally bench tested and run with no abnormalities revealed. Both of the magneto harnesses also bench tested satisfactorily. All of the spark plugs were removed and appeared normal. The carburetor bowl was opened and revealed no abnormal residues or contaminants. ## Aircraft - Registration: [N4008D](https://openairdocs.org/deregistered/N4008D-2019-05-16), registration cancelled 2019-05-16, S/N 1456, built 1990 (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: 1456 - Airframe hours: 5400 - Engines: Lycoming O-320 B2C 160 horsepower reciprocating - Damage: Destroyed - Flight: Instructional, Part 91 - Registered owner: Delta Leasing Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 21, 1997, 14 hours before - Departed: CHD, AZ - Airport: L07, Memorial, runway 30, 8,000 × 50 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; commercial, flight instructor; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 1,033 total, 471 in this make and model, 900 as pilot in command, 308 in the last 90 days, 126 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 12 knots - Visibility: 50 statute miles - Lowest ceiling: none - Temperature: 106 °F, dew point 50 °F - Altimeter: 29.00 inHg - Observed at: FFZ, 18 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 19970725019709A](https://openairdocs.org/incident/19970725019709A), Jul 25, 1997: Robsin R22BETA, Chandler, AZ, Destroyed. Indicates helicopter entered settling with power due turbulence and control inputs. No mechanical defects found. 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.