# NTSB SEA97GA008: Piper PA-18-150, N91017, Holden, UT, October 10, 1996 - Type: NTSB accident investigation - Classification: Accident · Fatal · Final report - Date: October 10, 1996, 07:55 local (13:55 UTC) - Place: Holden, UT - Coordinates: 39.139389, -112.340614 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.1394&lon=-112.3406&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report March 31, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 42515 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA97GA008 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42515/pdf - Page: https://openairdocs.org/ntsb/SEA97GA008 ## Probable cause The first pilot's failure to maintain adequate airspeed while maneuvering the airplane in close proximity to the ground. This subsequently led to an aerodynamic stall and uncontrolled descent into the ground. Factors contributing to the accident include the lack of adequate altitude to recover from the stall, the pilot's failure to operate the airplane within its published weight and balance envelope, and high density altitude. ## Analysis The first pilot, seated in the front seat of the public use airplane, was banking the airplane to the left while flying in close proximity to the ground over an open field in pursuit of running coyote. The first pilot was in the second phase of an agency training program. The second pilot, acting as a part-time instructor pilot/gunner and seated in the rear seat, was pointing a shotgun outside the airplane in an attempt to kill the coyote as per the agency's aerial hunting program. The airplane aerodynamically stalled during the maneuver and entered an uncontrolled descent; it impacted the ground in a near-vertical, inverted attitude and was destroyed. An examination of the airframe and engine did not reveal any evidence of preimpact mechanical malfunctions. The airplane was about 75 pounds over its published maximum gross weight, and the density altitude was about 6,500 feet during the accident. Unapproved modifications to the airplane and inadequate maintenance record keeping by the operator were found during the investigation. The second pilot's throttle handle was not installed in the throttle control at the time of the accident. ## Factual narrative HISTORY OF FLIGHT On October 10, 1996, at 0755 mountain daylight time, N91017, a Piper PA-18-150, operated by the Utah State Department of Agriculture, collided with terrain during an uncontrolled descent and was destroyed near Holden, Utah. Both commercial pilots were fatally injured. Visual meteorological conditions prevailed and an agency flight plan had been filed. The public use flight had departed from Delta, Utah, about 0730, and was conducted under 14 CFR 91. According to the operator of the aircraft, the purpose of the flight was for the aerial hunting of coyotes in accordance with a state and federal government program know as the Animal Damage Control (ADC) program. The ADC program is a part of the United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS). The flight had been scheduled as a result of reports from a local ranch owner that calves were being attacked and killed by coyotes on the ranch owner's property. The flight was manned by the first pilot (pilot-in-command), seated in the front seat, and the "co-pilot/gunner," (second pilot) seated in the rear seat. The co-pilot/gunner was also serving as an instructor pilot during portions of the flight. According to calendar book entries (copies of excerpts attached) made by the first pilot, he and the second pilot had flown for a total of 3.6 hours in the accident airplane one day previous to the accident. The entry, dated October 9, 1996, indicated that five coyotes had been killed, and that the crew had been on duty from 0700 until 1600, with the majority of the flying conducted in the morning. No entries indicating any aircraft anomalies were noted. Another entry under the same date was found to indicate that the airplane had received 25.5 gallons of 100 low lead gasoline by the first pilot. According to the operator, the airplane was typically "topped off" after each day's flying. On the morning of the accident, the first pilot and second pilot ate breakfast with an acquaintance at a restaurant. The acquaintance reported that the crew did not complain of any problems with themselves or the airplane. The crew then proceeded to the Delta Municipal Airport, where the airplane was based, and departed on the flight. According to an eyewitness (statement attached) who was riding in a truck about one mile east of the accident site: "All I saw was the wing span as [the airplane entered a nose dive] right into the dirt.... It didn't look like they had any control at all." Another witness in the truck said that he did not note any engine problems, and that the airplane "... was probably 20 feet from the ground when I saw it and it was going straight down nose first." No other witnesses were found that observed the airplane prior to the descent into the ground, and no radio distress calls from the airplane were reported. The airplane impacted an open field and was destroyed. The accident occurred during daylight conditions at the following coordinates: North 39 degrees, 08.15 minutes; West 112 degrees, 17.61 minutes. AIRCRAFT INFORMATION The accident airplane, a Piper PA-18-150, was manufactured in 1981. It had been owned by the Utah State Department of Agriculture, and operated by the cooperative USDA-UDA ADC Program since that time. It was powered by a single Lycoming 160-horsepower model O-320-B2B engine, and had been configured as an aerial hunting aircraft. The Safety Board collected and examined copies of maintenance records for the aircraft that were obtained from the operator. The examination revealed that the airplane had received an annual inspection on July 18, 1996, with no unresolved discrepancies noted. The airplane had logged a total of 7,944 hours at the time of the inspection, and had been flown for an additional 72 hours until the accident. The entry documenting the most recent annual inspection indicated that a factory overhauled Lycoming model O-320-B2B engine had been installed on the airframe on July 18, 1996. This engine replaced the original 150-horsepower Lycoming O-320-A2B engine that had been delivered with the airplane. According to the Type Certificate Holder Aircraft Specifications, the -B2B is not approved for use on the PA-18-150. No FAA form 337 was found for the installation of the -B2B. According to the operator, the FAA Salt Lake City Flight Standards District Office was informed of the installation but elected not to require an FAA form 337 for a major repair and/or alteration. Further review of the maintenance records revealed that the most recent weight and balance data sheet was dated May 4, 1987, when two FM radios were installed. According to Lycoming, the weight of the -B2B engine is 6 pounds heavier than the -A2B engine. No evidence was found to indicate that a modification to the airplane's weight and balance had been performed at the time of the installation. The maintenance record entries were found to document the installation of an intercom system in 1989, as well as an FM radio in 1996. No evidence was found to indicate that a modification to the airplane's weight and balance had been performed at the times of the installations. The aircraft was equipped with an "Automatic Flagman" ribbon dispenser unit mounted on the right main landing gear. No entries were found in the maintenance log book to document this installation. Based on the most recent weight and balance data sheet, estimated fuel load and subsequent consumption, weight records of both occupants, and estimated weights of the cargo and equipment found on board the airplane, the Safety Board computed what the weight and balance of the airplane would have been at the time of the accident (computation attached). The computation revealed that the airplane was about 75 pounds over it's published maximum gross weight of 1,750 pounds. No record of weight and balance for the accident flight was found, despite published agency requirements (excerpts attached). According to the New Piper Aircraft Corporation, the published stall speed of the Piper PA-18-150 in level flight, at maximum gross weight, flaps up, at sea level, is 43 miles per hour. The stall speed would increase with an increase in gross weight and/or bank angle. PERSONNEL INFORMATION First Pilot Information. The first pilot, age 41, seated in the front seat, held an FAA commercial pilot certificate with a rating for airplane single-engine land. According to FAA records, the pilot was issued an FAA Second Class Medical Certificate on February 22, 1996, with no limitations. The first pilot's personal flight log books and ADC training records (copies of excerpts attached) were recovered and examined by the Safety Board. According to entries found in the log books, the pilot had logged a total of 586 hours of flight time, including 460 hours of pilot-in-command time in the Piper PA-18-150, at the time of the accident. Prior to becoming a pilot, the first pilot had been employed by the Utah ADC program for about 5 years as a fixed-wing gunner and field technician. In a letter (copy attached) dated October 24, 1995, by the Acting Director of the ADC Western Region program, the first pilot was given a waiver to begin training as an ADC pilot without the required 150 flight hours. The letter stated that the pilot had entered an "accelerated flight training program to obtain the required private pilot certificate and [obtained] 100 hours of flight time." According to an ADC "Daily Pilot Training Report" (attached) dated April 30, 1996, the first pilot had been endorsed by the second pilot as completing the required training for Phase I. The pilot had logged 100 hours of front seat pilot time and a total flight time of 394 hours at the time of the endorsement. On August 20, 1996, the pilot successfully passed an ADC fixed wing pilot proficiency check (copy of flight c ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, maneuvering - weather condition - high density altitude (contributing factor) - low altitude flight/maneuver - required, pilot in command - throttle/power lever - not installed - airspeed - inadequate, pilot in command (cause) - stall - inadvertent, pilot in command (cause) - aircraft weight and balance - exceeded, pilot in command (contributing factor) - maintenance,recordkeeping - inadequate, company/operator management - maintenance,modification - not approved, company maintenance personnel - In flight collision with terrain/water, descent - uncontrolled - terrain condition - open field - altitude - inadequate (contributing factor) ## Aircraft - Registration: [N91017](https://openairdocs.org/deregistered/N91017-2015-04-30), registration cancelled 2015-04-30, S/N 18-8109062, built 1981 (OpenAirDocs) - Reported make and model: Piper PA-18-150 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-8109062 - Airframe hours: 8016 - Engines: Lycoming O-320-B2B 160 horsepower reciprocating - Damage: Destroyed - Flight: Public aircraft, Part 91 - Registered owner: Utah Dept. Of Agriculture - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 18, 1996, 72 hours before - Departed: DTA, DELTA, UT - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: front; toxicology performed; flight hours: 587 total, 461 in this make and model, 550 as pilot in command, 50 in the last 90 days, 27 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 60 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 27 °F - Altimeter: 30.00 inHg - Observed at: CDC, 75 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 19961010031479A](https://openairdocs.org/incident/19961010031479A), Oct 10, 1996: Piper PA18150, Holden, UT, Destroyed, 2 fatal. The first pilot, seated in the front seat of the public use airplane, was banking the airplane to the left while flying in close proximity to the ground over… 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.