# NTSB NYC06TA190: MD Helicopter 500N, N520AP, Louisville, KY, August 2, 2006 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Final report - Date: August 2, 2006, 13:20 local (17:20 UTC) - Place: Louisville, KY - Coordinates: 38.13972, -85.539169 - Nearby events: https://openairdocs.org/map.md?lat=38.1397&lon=-85.5392&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report June 27, 2007 - Report: Approved by Office Director - Parties: MD Helicopters Inc., FAA/FSDO - NTSB case key (mKey): 64256 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC06TA190 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64256/pdf - Page: https://openairdocs.org/ntsb/NYC06TA190 ## Probable cause The pilot's failure to maintain control of the helicopter and the flight instructor's inadequate supervision, which resulted in a hard landing and subsequent rollover. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, landing - aircraft control - not maintained, dual student (cause) - supervision - inadequate, pilot in command(cfi) (cause) - Hard landing, descent - uncontrolled - terrain condition - ground - Roll over, descent - uncontrolled ## Analysis The flight instructor was providing initial helicopter training to the student, a commercial pilot with fixed wing ratings. The student, with the flight instructor "following closely" on the controls, was practicing approaches to a hover in an open field. After several approaches, they decided to practice a steep approach. About 600 feet above the ground the student began a stabilized approach at 40 knots indicated airspeed, and at a descent rate about 1,000 feet per minute. He then brought the helicopter to a hover about 5 to 10 feet above the ground. The helicopter hovered for between 5 and 15 seconds, before it "drop[ed] to the ground," and rolled onto its right side. The flight instructor further reported that prior to the accident, the helicopter was operating with "no indication of [a] mechanical problem," and the engine seemed to be producing power normally. A witness stated that as the helicopter got close to the ground, "it all of the sudden pitched nose down," and impacted the ground. Examination of the wreckage revealed that both right landing gear struts fractured in ductile overload, consistent with a single impact. Flight control continuity was established, with no anomalies noted. ## Factual narrative On August 2, 2006, at 1320 eastern daylight time, a MD Helicopter Inc. 500N, N520AP, was substantially damaged when it impacted terrain during an uncontrolled descent, near Louisville, Kentucky. The certificated flight instructor was not injured, and the certificated commercial pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional flight conducted under 14 CFR Part 91. According to the flight instructor, he was providing initial helicopter training to the student, a commercial pilot with fixed wing ratings. The student, with the flight instructor "following closely" on the controls, was practicing approaches to a hover in an open field. After several approaches, they decided to practice a steep approach. About 600 feet above the ground, the student began a stabilized approach at 40 knots indicated airspeed, and at a descent rate about 1,000 feet per minute. He then brought the helicopter to a hover about 5 to 10 feet above the ground. The helicopter hovered for between 5 and 15 seconds, on a northerly heading, before it "seemed to drop to the ground." The flight instructor recalled that the helicopter dropped straight down, with no lateral movement, then rolled onto its right side. The engine continued to run for about 10 seconds until it shut down. The flight instructor further reported that prior to the accident, the helicopter was operating with "no indication of [a] mechanical problem," and the engine seemed to be producing power normally. At the time of the accident, the winds were from the northwest at a velocity of about 10 to 15 knots. According to the student, they approached the field in a stabilized descent about 60 knots indicated airspeed. He then arrested the descent, and entered a hover about 10 feet above the ground. While stabilizing the hover, the student felt a sensation of descending very rapidly. The next thing he remembered, the helicopter was on its side, and the engine and rotor blades were coming to a stop. Two witnesses observed the helicopter before and during the accident. One witness reported seeing the helicopter as she drove on a road adjacent to the landing field. She described that the helicopter looked like it was going to land "normally," but that as it got close to the ground, "it all of the sudden pitched nose down," and impacted the ground. When asked if the helicopter had hovered or paused in the air, she stated that it continually moved forward and down during the approach, then "just hit the ground." The other witness reported seeing the helicopter as it approached the field. She stated that the helicopter descended, paused for a moment near the ground, then impacted the ground. The flight instructor held a commercial pilot certificate with ratings for airplane single engine land and rotorcraft-helicopter, and a flight instructor certificate with a rating for rotorcraft. He reported 2,028 total hours of flight experience, 1,860 hours of which were in rotorcraft, and 740 hours of which were in the accident helicopter make and model. The student held a commercial pilot certificate with ratings for airplane single and multiengine land, and instrument airplane. He reported 345 total hours of flight experience, 5 hours of which were in rotorcraft, all in the accident helicopter make and model. Representatives from the airframe and engine manufacturers, as well as a Federal Aviation Administration (FAA) inspector, examined the wreckage following the accident. The helicopter came to rest on its right side, and both the right forward and rear landing gear struts were fractured about 14 inches from the fuselage. Examination of the forward strut fuselage access hole revealed that it was elongated in the forward and aft direction. There was damage to the right chin bubble and associated structure directly below the right side pedal assembly, and the pitot tube was bent slightly left and caked inside with mud. All of the main rotor blades exhibited extensive damage consistent with ground contact, and there were several ground scars nearby that were of a similar width as the main rotor blades. Flight control continuity was established, with no anomalies noted. Both portions of the front and rear fractured landing gear were removed and sent to a laboratory for further analysis. No evidence of corrosion or fatigue was found on any of the fracture surfaces. Examination of both the front and rear struts revealed that they exhibited signatures consistent with ductile overload during a single impact. The weather reported at Bowman Field Airport (LOU), Louisville, Kentucky, located about 8 nautical miles northwest, at 1253, included winds from 280 degrees at 9 knots, temperature 91 degrees Fahrenheit, dewpoint 73 degrees Fahrenheit, and an altimeter setting of 30.02 inches of mercury. ## Aircraft - Registration: [N520AP](https://openairdocs.org/aircraft/N520AP), registered now, S/N LN095, built 2001 (OpenAirDocs) - Reported make and model: MD Helicopter Inc. 500N - Registry model: [MD Helicopters 500N](https://openairdocs.org/model/md-helicopters-500n) (registry code 3030001) (OpenAirDocs) - Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: LN095 - Airframe hours: 4116 - Engines: Allison 250-C20R/2 450 horsepower turbo shaft - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Louisville Metro Police Department - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 1, 2006 - Departed: NONE, Louisville, KY - Destination: NONE ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 52; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review November 1, 2005; seat: right; flight hours: 2,028 total, 740 in this make and model, 1,781 as pilot in command, 50 in the last 90 days, 28 in the last 30 days, 6 in the last 24 hours - Pilot; age 38; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; last flight review March 1, 2003; seat: right; flight hours: 345 total, 5 in this make and model, 203 as pilot in command, 5 in the last 90 days, 5 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 73 °F - Altimeter: 30.02 inHg - Observed at: LOU, 8 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 20060802017559A](https://openairdocs.org/incident/20060802017559A), Aug 2, 2006: Hughes 500N, Louisville, KY, Substantial damage. (-23) Helicopter crashed resulting in one pilot sustaining fractured vertebra and causing substantial damage to the aircraft. Pilot's statements indicate that… 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.