# NTSB DFW07LA043: Eurocopter EC120B, N171AE, Grand Prairie, TX, December 21, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 21, 2006, 15:10 local (21:10 UTC) - Place: Grand Prairie, TX - Coordinates: 32.698612, -97.046943 - Nearby events: https://openairdocs.org/map.md?lat=32.6986&lon=-97.0469&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 27, 2007 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 65056 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW07LA043 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65056/pdf - Page: https://openairdocs.org/ntsb/DFW07LA043 ## Probable cause The flight instructor's inadequate remedial action which resulted in a hard landing. A contributing factor was the lack of suitable terrain for the practice autorotation. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, landing - rotor rpm - not maintained, dual student - remedial action - inadequate, pilot in command(cfi) (cause) - Loss of control - on ground/water, landing - terrain condition - soft - unsuitable terrain or takeoff/landing/taxi area - misjudged, pilot in command(cfi) (contributing factor) - Roll over, landing - roll ## Analysis While performing a practice 180-degree autorotation, the 5,943-hour flight instructor observed that the student would not make the landing area. The flight instructor took over the helicopter controls and elected to land in the grass near the runway. The helicopter touched-down hard with low rotor energy and at a higher than normal touchdown speed. The helicopter proceeded to skid on the soft grass before digging in and rolling forward on its nose. The rotor blades subsequently impacted the ground before the helicopter rolled and came to rest on its right side. The pilot did not report any abnormalities with the helicopter's flight controls. The winds at the time of the mishap were reported from 260-degrees at 6 knots. The practice area used for the practice autorotations was aligned on a heading of 170-degrees. ## Factual narrative On December 21, 2006, about 1510 central standard time, a single-engine Eurocopter EC120B turbine powered helicopter, N171AE, was substantially damaged during a hard landing following a practice autorotation at the Grand Prairie Municipal Airport (GPM), near Grand Prairie, Texas. The flight instructor and student pilot were not injured. The helicopter was registered to Wells Fargo Bank Northwest of Salt Lake City, Utah, and was operated by American Eurocopter of Grand Prairie, Texas. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 instructional flight. The local flight originated from GPM approximately 1430. In a written statement, the 5,943-hour flight instructor reported that during the instructional flight, the student pilot had completed multiple autorotations prior to the accident. On previous landings, the flight instructor noted that "the ground was soft and the aircraft demonstrated a propensity to pitch nose forward on two of the previous touchdowns". The student pilot was executing his fourth 180-degree autorotation to the west grass landing area parallel to Runway 17 when the accident occurred. According to the flight instructor, the student pilot made an appropriate autorotational entry and started his 180-degree turn for a final heading of between 220-degrees and 270-degrees. The flight instructor noted that as they passed through a heading of 200-degrees, the approach became steeper as the helicopter turned into the wind. Passing through approximately 70-feet above the ground (agl), the flight instructor observed that the student pilot would not make the landing area and that there was "no time to power-recover." The flight instructor added that he took over the helicopter controls and elected to land in the grass near the runway. According to the flight instructor, "[the helicopter] touched down with low rotor energy and what seemed like a higher touchdown speed than during runway touchdowns." The helicopter proceeded to skid on the soft grass before digging in and rolling forward on its nose. The rotor blades subsequently impacted the ground before the helicopter rolled and came to rest on its right side. Both pilots were able to exit the helicopter unassisted. An inspector from the Federal Aviation Administration (FAA) responded to the accident site. According to the inspector, the helicopter's tail boom and horizontal stabilizer sustained structural damage. The pilot did not report any abnormalities with the helicopter's flight controls. At 1455, the weather observation facility at GPM reported, wind from 260-degrees at 6 knots, visibility 10 statute miles, clear of clouds, temperature 59 degrees Fahrenheit, dew point 32 degrees Fahrenheit, and a barometric pressure of 29.98 inches of Mercury. ## Aircraft - Registration: [N171AE](https://openairdocs.org/deregistered/N171AE-2016-09-19), registration cancelled 2016-09-19, S/N 1377, built 2004 (OpenAirDocs) - Reported make and model: Eurocopter EC120B - Registry model: [Eurocopter EC120B](https://openairdocs.org/model/eurocopter-ec120b) (registry code 8680987) (OpenAirDocs) - Registry engine: [Turbomeca ARRIUS-2F](https://openairdocs.org/engine/turbomeca-arrius-2f) (registry code 60010, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 1377 - Airframe hours: 777 - Engines: Turbomeca Arrius 2F 504 horsepower turbo shaft - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: American Eurocopter - Registered owner: Wells Fargo Bank - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 1, 2006 - Departed: GPM, Grand Prairie, TX - Airport: KGPM, Grand Prairie Municipal ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 51; injuries: none; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review August 1, 2006; seat: left; flight hours: 5,943 total, 370 in this make and model, 5,083 as pilot in command, 143 in the last 90 days, 68 in the last 30 days, 5 in the last 24 hours - Student pilot; age 46; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, without waivers/limitations; last flight review August 1, 2006; seat: right ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 32 °F - Altimeter: 29.97 inHg - Observed at: GPM ## 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 20061221025689A](https://openairdocs.org/incident/20061221025689A), Dec 21, 2006: Urocop EC120B, Grand Prairie, TX, Substantial damage. (-23) Instructor pilot [privacy data omitted] ^ and student [privacy data omitted] were performing 180 degree autorotations to a grass area at Grand Prairie… 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.