# NTSB ANC06LA073: MBB BK 117A-3, N913EF, Ponce de Leon, FL, June 22, 2006 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: June 22, 2006, 01:30 local (06:30 UTC) - Place: Ponce de Leon, FL - Coordinates: 30.848888, -85.695274 - Nearby events: https://openairdocs.org/map.md?lat=30.8489&lon=-85.6953&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 2 uninjured - Status: Completed, report April 25, 2007 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 63960 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC06LA073 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/63960/pdf - Page: https://openairdocs.org/ntsb/ANC06LA073 ## Probable cause The pilot's failure to maintain clearance from objects while hovering in ground effect, which resulted in an in-flight collision with a tree. Factors associated with the accident were loose, sand-covered terrain, and the operator's failure to ensure that the pilot was provided with current, off-airport landing site condition information. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, hover - in ground effect - clearance - not maintained, pilot in command (cause) - unsafe/hazardous condition - not identified, company/operator management (contributing factor) - terrain condition - loose gravel/sandy (contributing factor) - object - tree(s) - light condition - night - Loss of control - in flight, hover - in ground effect - In flight collision with terrain/water, descent - uncontrolled - terrain condition - ground ## Analysis The commercial certificated pilot was transporting two medical crewmembers under Title 14, CFR Part 91, to a prearranged landing site to meet ambulance and fire department personnel caring for a patient. The flight was conducted during dark night conditions. The accident helicopter had predetermined landing site locations stored in its onboard GPS navigation system. The stored landing sites had been previously inspected for obstruction clearance and overall suitability. After arriving overhead of what he thought was a sod-covered field, the pilot used an externally mounted searchlight to aid in seeing the ground and obstructions during the landing approach. As the helicopter approached the open field and transitioned from forward flight to a hover, the pilot encountered blowing, dry sand and dust created by the helicopter's main rotor downwash, which reduced his visibility. He stated he lost all visual reference with the surface of the field, and while attempting to regain a visual reference, the helicopter's main rotor struck a large tree, and the fuselage began to rotate. The helicopter's tail boom assembly subsequently struck the tree, and the helicopter impacted terrain. The helicopter sustained substantial damage to the main rotor drive system, tail boom assembly, and fuselage. A postaccident inspection of the landing site disclosed that the sod had recently been removed from the field, leaving a dry, sand-covered field. The pilot reported that there were no preaccident mechanical anomalies with the helicopter. ## Factual narrative On June 22, 2006, about 0130 central daylight time, a skid-equipped Messerschmitt-Bolkow-Blohm (MBB) BK 117A-3 helicopter, N913EF, sustained substantial damage after colliding with trees while landing at an off-airport site, about 10 miles north of Ponce de Leon, Florida. The helicopter was being operated as a visual flight rules (VFR) emergency medical services (EMS) positioning flight under Title 14, CFR Part 91, when the accident occurred. Of the three occupants aboard, the certificated commercial helicopter pilot and one medical crewmember were not injured. The remaining medical crewmember sustained minor injuries. The helicopter was operated by CJ Systems Aviation Group, of West Mifflin, Pennsylvania. The medical facility, Doctor's Memorial Hospital, based in Bonifay, Florida, was utilizing CJ Systems Aviation Group to provide EMS helicopter transport services. The helicopter was en route to a prearranged landing site to meet ambulance and fire department personnel caring for a patient. Dark night, visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight originated about 0110, from the Tri-County Airport, Bonifay. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on June 22, the pilot reported that he was transporting two flight paramedics to a rural community located in Holmes County to pickup a maternity patient. He said that pilots use a number of prearranged landing sites in the area, which have been previously inspected for obstruction clearance, as well as the overall site condition. According to the pilot, these prearranged landing site locations are stored in the helicopter's onboard GPS navigation system. The pilot said that during the outbound flight, fire department personnel contacted him via radio and requested that the landing site be changed to another prearranged landing site, a sod-covered open field. He agreed to the change, selected the new landing site from coordinates previously stored in the GPS, and went to the new site. He reported that after arriving overhead of what he thought was a sod-covered field, he used an externally mounted searchlight to aid in seeing the ground and obstructions during the landing approach. As the helicopter approached the open field, and transitioned from forward flight to a hover, the pilot said he encountered a substantial amount of blowing, dry sand and dust created by the helicopter's main rotor downwash, which momentarily reduced his visibility. He stated he lost all visual reference with the surface of the field, and while attempting to regain a visual reference, the helicopter's main rotor struck a large tree, and began to spin. The helicopter's tail boom assembly subsequently struck the tree, and the helicopter impacted terrain. The helicopter sustained substantial damage to the main rotor drive system, tail boom assembly, and fuselage. The pilot reported that there were no preaccident mechanical anomalies with the helicopter. A postaccident inspection of the landing site disclosed that the sod had recently been removed from the field, leaving a dry, sand-covered field. ## Aircraft - Registration: [N913EF](https://openairdocs.org/deregistered/N913EF-2013-08-16), registration cancelled 2013-08-16, S/N S-7032 (OpenAirDocs) - Reported make and model: MBB BK 117A-3 - Registry model: [Messerschmitt BK 117](https://openairdocs.org/model/messerschmitt-bk-117) (registry code 5626010) (OpenAirDocs) - Category: Helicopter - Serial number: 7032 - Airframe hours: 8882.3 - Engines: Lycoming LTS101-650-B1 600 horsepower turbo shaft - Damage: Substantial damage - Flight: Positioning, Part 91 - Operator: Corporate Jets Inc, doing business as CJ Systems Aviation Group - Registered owner: PNC Bank and Trust - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, June 1, 2006, 8.8 hours before - Departed: 02FD, Bonifay, FL - Destination: Prosperity, FL - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; commercial; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review April 1, 2006; seat: right; flight hours: 4,726 total, 66 in this make and model, 3,500 as pilot in command, 48 in the last 90 days, 9 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 230° at 3 knots - Visibility: 6 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 68 °F - Altimeter: 30.12 inHg ## 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 20060622014289A](https://openairdocs.org/incident/20060622014289A), Jun 22, 2006: Bolkms BK117A1, Westville, FL, Substantial damage. (-23) The landing zone in use had been surveyed and preapproved for use by the air carrier and county officials. The lz had been dug up and graded in… 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.