# NTSB DFW06LA130: Grumman G-164A, N6629, DeWitt, AR, May 18, 2006 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: May 18, 2006, 12:10 local (17:10 UTC) - Place: DeWitt, AR - Coordinates: 34.219165, -91.313888 - Nearby events: https://openairdocs.org/map.md?lat=34.2192&lon=-91.3139&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal, 1 serious - Status: Completed, report July 2, 2009 - Report: Approved by Office Director - Parties: FAA, FSDO - NTSB case key (mKey): 63707 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW06LA130 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/63707/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=63707 - Page: https://openairdocs.org/ntsb/DFW06LA130 ## Probable cause (aircraft 2) The failure by both pilots to maintain adequate visual lookout and the Grumman G-164A pilot's impairment caused by the recent use of marijuana. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, cruise - visual lookout - inadequate, pilot in command (cause) - impairment(drugs), pilot in command (cause) - Loss of control - in flight, descent - uncontrolled - In flight collision with terrain/water, descent - uncontrolled - terrain condition - ground - Midair collision, maneuvering - aerial application - visual lookout - inadequate, pilot in command (cause) - impairment(drugs), pilot of other aircraft (cause) - Loss of control - in flight, descent - uncontrolled - In flight collision with terrain/water, descent - uncontrolled - terrain condition - ground ## Analysis (aircraft 2) The 5,700-hour commercial pilot of a turbine powered agricultural bi-plane had completed an aerial application run, and was returning on a northerly heading to the municipal airport in order to pickup another load of fertilizer. The owner of the bi-plane stated that it's typical for the pilot to fly between 200 and 300 feet above the ground en route to, or from the airport. A 12,300-hour commercial pilot of an agricultural, turbine powered low-wing airplane departed a private airstrip, located west of the municipal airport, and was heading in a southeasterly direction en route to deliver his aerial application load. The airplanes collided in-flight while en route to their destinations and there was no reported witnesses to the event. The weather in the area was reported as VFR (Visual Flight Rules). The GPS logging unit was not installed in bi-plane at the time of the accident. The GPS memory card from the low-wing airplane was removed and sent to the manufacturer for download. However, the GPS manufacturer reported that the unit was not recording information at the time, and no data was available with regards to the accident. The Federal Aviation Administration's Civil Aerospace Medical Institute conducted toxicology tests on the remains of the Grumman G-164A pilot. Tetrahydrocannabinol (THC/marijuana) was detected in the pilot's heart and lung tissue. Tetrahydrocannabinol carboxylic acid (THC-COOH, a marijuana metabolite) was detected in lung, heart and urine samples. The testing indicated that the pilot had recently used marijuana, which resulted in his impairment. ## Factual narrative (aircraft 2) On May 18, 2006, approximately 1210 central daylight time, a Grumman G-164A, agricultural bi-plane, N6629, and an Ayres S2R low-wing agricultural airplane, N4121G, collided in-flight while maneuvering near DeWitt, Arkansas. Both airplanes sustained substantial damage. The commercial pilot and sole occupant of the G-164A was fatally injured. The commercial pilot and sole occupant of the S2R, received serious injuries. The G-164A was registered to Aufderheide Flying Service, Inc., of DeWitt, Arkansas, and operated by an individual. The S2R was registered to and operated by Wilco Flying Service, LLC., of DeWitt, Arkansas. Visual meteorological conditions prevailed and flight plans were not filed for either flight. Both airplanes were operating under 14 Code of Federal Regulations Part 137 for aerial application flight. The Grumman G-164A Ag-Cat is a turbine powered bi-plane and has conventional landing gear, a single-seat and was initially fitted with a piston (reciprocating) engine. A popular conversion for the Ag-Cat is the replacement of the reciprocating engine with a turbine engine. The Ayres S2R Thrush is a single seat, low wing airplane with conventional landing gear. The accident airplane was powered with a Pratt & Whitney PT6A series turbine engine. There were no reported eyewitnesses to the accident; however the owner of the G-164A stated that his pilot was returning to DeWitt Municipal Airport, 5M1, (located approximately 3 miles southeast of the city) from an aerial application flight. The owner also reported that the field the pilot was working was located approximately 2 to 3 miles directly south of the accident site. The general location of the field and the airport would put the pilot of the G-164A bi-plane returning to the airport on a northerly heading. The owner also added that it's typical to fly between 200-300 feet above the ground when en-route to, and from the airport. The pilot of the S2R told the NTSB Investigator-in-Charge (IIC) that he departed a private airstrip, located about a mile west of DeWitt and was en route to his field, which was located approximately three-quarters of a mile south of the accident site. The general location of the private airstrip and the field being worked would put the pilot of the S2R on a southeasterly heading. The pilot also reported that he didn't recall seeing anything other than "maybe a flash" just before "fighting the controls" during the uncontrolled descent to the ground. At 1155, the automated weather observing system at Stuttgart Municipal airport (SGT), near Stuttgart, Arkansas, located approximately 26 miles northwest of the accident site, reported wind from 320 degrees at 11 knots, 10 statute miles visibility, a clear sky, temperature 79 degrees Fahrenheit, dew point 55 degrees Fahrenheit, and an altimeter setting of 29.87 inches of Mercury. A review of Federal Aviation Regulation (FAR) (Section 91.113(b): Right-of-way rules) states in part: When weather conditions permit, vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft. Additionally, FAR 91.113(d) states: When aircraft of the same category are converging at approximately the same altitude (except head-on, or nearly so), the aircraft to the other's right has the right-of-way. In selecting a cruising altitude the general requirements of FAR 91.159 apply; that on a magnetic course of 0 through 179 degrees, choose an altitude of, odd thousand altitude, plus 500 feet; on a magnetic course of 180 through 359 degrees, choose an even thousand, plus 500 feet. The FAR also states that the requirement for selecting an altitude based on aircraft course is only applicable at attitudes above 3,000 feet above the surface. The GPS logging unit was not installed in the G-164A at the time of the accident. The GPS memory card from the S2R was removed and sent to the manufacturer for further download. However, the GPS manufacturer reported that the unit was not recording information at the time of the accident, and no data was available with regards to the accident. The Federal Aviation Administration’s Civil Aerospace Medical Institute conducted toxicology tests on the remains of the Grumman G-164A pilot. Tetrahydrocannabinol (THC/marijuana) was detected in the pilot’s heart and lung tissue. Tetrahydrocannabinol carboxylic acid (THC-COOH, a marijuana metabolite) was detected in lung, heart, and urine samples. The testing indicated that the pilot had recently used marijuana, which resulted in his impairment. The Arkansas State Crime Laboratory, Medical Examiner Division, performed an autopsy on the G-164A pilot on May 19, 2006. The autopsy lists the cause of death as blunt force injuries sustained during an aircraft crash. The FAA Toxicology Accident Research Laboratory, near Oklahoma City, Oklahoma, conducted toxicological testing on the G-164A pilot. Tetrahydrocannabinol (Marihuana) was detected in the lung and heart. Tetrahydrocannabinol Carboxyic acid (Marihuana) was also detected in the liver, lung, heart, and urine. ## Aircraft 1 - Registration: [N6629](https://openairdocs.org/deregistered/N6629-2009-01-14), registration cancelled 2009-01-14, S/N 759, built 1970 (OpenAirDocs) - Reported make and model: Grumman G-164A - Registry model: [Grumman G-164A](https://openairdocs.org/model/grumman-g-164a) (registry code 3952704) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 759 - Engines: Garrett TPE-331 575 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Aufderheide Flying Service, Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, January 1, 2006 - Departed: 5M1, DE WITT, AR - Destination: De Witt, AR ## Aircraft 2 - Registration: [N4121G](https://openairdocs.org/deregistered/N4121G-2007-03-01), registration cancelled 2007-03-01, S/N T660-105, built 2000 (OpenAirDocs) - Reported make and model: Ayres S2R - Registry model: [Ayres S2R-T660](https://openairdocs.org/model/ayres-s2r-t660) (registry code 0970112) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52034, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: T660-105 - Airframe hours: 3174 - Engines: Pratt & Whitney PT6A 660 lbs thrust turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 1, 2006 - Departed: DeWitt, AR - Destination: DeWitt, AR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N6629; age 34; injuries: fatal; commercial; airplane ratings: single-engine land; medical: class 2, without waivers/limitations; last flight review March 1, 2005; seat: single; toxicology performed; flight hours: 5,700 total, 1,200 in this make and model, 5,300 as pilot in command, 75 in the last 90 days, 40 in the last 30 days, 10 in the last 24 hours - Pilot, aircraft N4121G; age 39; injuries: serious; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review January 1, 2006; seat: single; flight hours: 12,300 total, 3,200 in this make and model, 12,300 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 55 °F - Altimeter: 29.87 inHg - Observed at: SGT, 26 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 20060518010071A](https://openairdocs.org/incident/20060518010071A), May 18, 2006: Scwzer G164A, Dewitt, AR, Destroyed, 1 fatal. (-23) On may 18, 2006, at approximately 12:00 CDT, a Grumman G-164, N6629, collided with an ayers-S2R, N4121G. The ayers, N4121G, was ferrying a load of… - [Accident 20060518010072A](https://openairdocs.org/incident/20060518010072A), May 18, 2006: Ayres S2RT660, Dewitt, AR, Destroyed. (-23) On may 18, 2006, at approximately 12:00 CDT, a Grumman G-164, N6629, collided with an Ayres-S2R, N4121G. The Ayres, N4121G, was ferrying a load of… ## Docket (11 files) The files NTSB released with the investigation on September 14, 2006, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=63707. 2.3 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 406 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266491&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 282 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266492&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Maps or Charts of Accident Area, Wreckage Diagrams (item 3, .PDF, 241 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266493&FileExtension=.PDF&FileName=Maps%20or%20Charts%20of%20Accident%20Area,%20Wreckage%20Diagrams-Master.PDF - Weather Reports and Records (item 4, .PDF, 26 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266494&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF - Other Pertinent Forms and Reports (item 5, .PDF, 34 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377838&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports-Redacted.PDF - Toxicological Report (item 6, .PDF, 69 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266497&FileExtension=.PDF&FileName=Toxicological%20Report-Master.PDF - Site Photo 1 (item 7, .PDF, 22 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266508&FileExtension=.PDF&FileName=Site%20Photo%201-Master.PDF - Site Photo 2 (item 8, .PDF, 27 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266509&FileExtension=.PDF&FileName=Site%20Photo%202-Master.PDF - Site Photo 3 (item 9, .PDF, 29 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266510&FileExtension=.PDF&FileName=Site%20Photo%203-Master.PDF - Site Photo 4 (item 10, .PDF, 33 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40266511&FileExtension=.PDF&FileName=Site%20Photo%204-Master.PDF - NTSB Response to Petition For Reconsideration (item 11, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40315963&FileExtension=.PDF&FileName=NTSB%20Response%20to%20Petition%20For%20Reconsideration-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.