# NTSB NYC01LA179: McDonnell Douglas 369E, N577DB, Niagara Falls, NY, July 19, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 19, 2001, 15:40 local (19:40 UTC) - Place: Niagara Falls, NY - Coordinates: 43.099246, -78.949172 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.0992&lon=-78.9492&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 17, 2001 - Report: Approved by Office Director - Parties: FAA/FSDO - NTSB case key (mKey): 52772 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC01LA179 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52772/pdf - Page: https://openairdocs.org/ntsb/NYC01LA179 ## Probable cause The right skid getting snagged on the helicopter-dolly resulting in dynamic rollover. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Roll over, landing - landing gear,skid assembly - snagged (cause) ## Analysis The helicopter came to a hover over a helicopter-dolly in preparation for landing. The wind was to the front right of the helicopter as the pilot lowered the collective. As the helicopter touched down, the pilot felt that the right skid was not properly situated on the dolly. When he increased collective to reposition the helicopter, it rolled to the right, and impacted the ground. About 15 minutes after the accident, a weather facility located approximately 3 miles to the southeast of the accident site, recorded the wind as 8 knots. According to FAA AC 90-87, if a rolling moment is allowed to develop while one skid is in contact with the ground, a helicopter can exceed its critical rollover angle, and roll onto its side. The pilot had approximately 2,200 hours of total flight experience, all of which was in turbine helicopters, and about 200 hours of that was in the accident helicopter make and model. ## Factual narrative On July 19, 2001, about 1540 eastern daylight time, a McDonnell Douglas 369E, N577DB, was substantially damaged when it rolled over during landing, at the operator's facility in Niagara Falls, New York. The certificated commercial pilot was not injured. Visual meteorological conditions prevailed for the positioning flight that departed a helipad in Niagara Falls, New York, about 1530. No flight plan was filed, and the flight was conducted under 14 CFR Part 91. According to the pilot he was re positioning the helicopter so it could be placed in a hangar. He departed a helipad and flew about 4 minutes to the operator's facility. He then came to a hover over a helicopter-dolly with the wind to the front left of the helicopter. The pilot lowered the collective, and the helicopter touched down softly. The skids on the helicopter were lined up with the white touchdown markings, but the pilot felt that the right skid was not situated properly on the dolly. As the pilot increased collective to reposition the helicopter, it rolled to the right, and impacted the ground. The pilot then executed an emergency shut down, and exited the helicopter. According to a Federal Aviation Administration inspector, the landing surface on the helicopter-dolly was constructed of wooden boards that measured 8 inches wide by 2 inches thick. To hold the landing surface boards in place, there were two additional wooden boards, each measuring 4 inches wide by 2 inches thick, attached perpendicular to the underside of the landing surface with metal screws. Examination of the helicopter-dolly revealed that both sets of boards were intact, and that the metal screws had sheared consistent with overload. About 15 minutes after the accident, Niagara Falls International Airport (IAG), Niagara Falls, New York, which was located approximately 3 miles to the southeast of the accident site, recorded the following weather: wind 070 at 8 knots, visibility 12 miles, few clouds at 4,500 feet, ceiling 6,500 feet broken, 18,000 feet overcast, temperature 82 degrees Fahrenheit, dew point 68 degrees Fahrenheit, and an altimeter setting of 30.11 Hg. According to Advisory Circular 90-87, Helicopter Dynamic Rollover, if a rolling moment is allowed to develop while one skid is in contact with the ground, the helicopter can exceed its critical rollover angle. As the helicopter begins to roll, lateral cyclic control response becomes more sluggish and less effective than for a free hovering helicopter. As the roll rate increases, the angle at which recovery is still possible is significantly reduced. The pilot reported 2,200 hours of total flight experience, all of which was in turbine helicopters. The pilot added that he had about 200 hours in the accident helicopter make and model, with 35 hours of that being in the actual accident helicopter. ## Aircraft - Registration: [N577DB](https://openairdocs.org/deregistered/N577DB-2006-11-28), registration cancelled 2006-11-28, S/N 0381E, built 1990 (OpenAirDocs) - Reported make and model: McDonnell Douglas 369E - Registry model: [Mcdonnell Douglas Helicopter 369E](https://openairdocs.org/model/mcdonnell-douglas-helicopter-369e) (registry code 3027369) (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: 0381E - Airframe hours: 4588.4 - Engines: Allison 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Positioning, Part 91 - Registered owner: Rainbow Air, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 11, 2001, 20 hours before - Departed: IAG, NIAGARA FALLS, NY - Destination: Niagara Falls, NY ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; commercial; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; last flight review May 23, 2001; seat: left; flight hours: 2,217 total, 226 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 8 knots - Visibility: 12 statute miles - Lowest ceiling: 6,000 ft broken - Temperature: 82 °F, dew point 68 °F - Altimeter: 30.11 inHg - Observed at: IAG, 3 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 20010719017789A](https://openairdocs.org/incident/20010719017789A), Jul 19, 2001: Hughes 369E, Niagarafalls, NY, No damage. (-23) On Thursday, July 19, 2001 at 1530 EDT, a HU-369E helicopter, N577DB, operated by rainbow air, inc., niagara falls, new york, landed on a mobile pad and… 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.