Individually Owned: 150,657
Corporate Owned: 137,281
Wiley Post Airport
Aircraft Accident/Incident Report
Bethany, Oklahoma 73008
Thursday, May 16, 1996 15:00 CDT
NTSB Narrative Summary Released at Completion of Accident
Prior to the landing, the instructor pilot verified the wind from the tower (180 degrees at 19 knots, gusting to 22 knots). With the helicopter stable on the ground, downwind from a nearby building, the flight controls were frictioned down and normal shut down procedures were started. Passing through 19% rotor RPM, the rotor brake was applied. To demonstrate that the rotor would continue turning without rotor brake application, the instructor released the brake at 10% RPM and allowed the rotors to turn down to 9% RPM. The rotor brake was then re-applied, and while the rotor was decelerating, 'two or three thumps were heard', and the instructor observed the rotors 'jerk and come to a stop.' The instructor stated that wind being redirected around the building may have caused the rotors to flap down into the tail boom. Examination of the aircraft revealed that at least two of the three main rotors contacted the tail boom. No mechanical defects were found in the flight control and rotor systems. According to the manufacturer's flight manual, the shut down sequence and rotor brake application were conducted in accordance with current published procedures.
NTSB Probable Cause Narrative
The main rotor blades' contact with the tail boom due to gusting winds during rotor deceleration.
Event Information
| Type of Event | Accident |
| Event Date | 5/16/1996 |
| Event Day of the Week | Thursday |
| Time of Event | 1500 |
| Event Time Zone | Central Daylight Time |
| Event City | BETHANY |
| Event State | OKLAHOMA |
| Event Country | -- |
| Zipcode of the event site | 73008 |
| Event Date Year | 1996 |
| Event Date Month | 5 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | WILEY POST |
| Event Location Nearest Airport ID | PWA |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | 1299 |
| Weather Briefing Completeness | Partial - limited by pilot |
| Investigator's weather source | Pilot |
| Time of the weather observation | 0 |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | |
| Elevation of weather observation facility | 0 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 15 |
| Air Temperature at event time (in degrees celsius) | -- |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | 180 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 19 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 22 |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 2 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 1278 |
| NTSB Notification Source | -- |
| NTSB Notification Date | May 22 1996 12:00AM |
| NTSB Notification Time | 1058 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Dec 8 2000 10:00AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N520DD |
| NTSB Number | FTW96TA222 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | McDonnell Douglas |
| Aircraft Model | MD-520N |
| Aircraft Series Identifier | MD-520N |
| Aircraft Serial Number | LN0030 |
| Certified Max Gross Weight | 3350 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 5 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Sep 1 1995 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 185 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | FAA |
| Aircraft Owner Street Address | 1601 NORTHWEST EXPWY, BOX 51 |
| Aircraft Owner City | OKLAHOMA CITY |
| Aircraft Owner State | OK |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 73118 |
| Operator is an individual? | -- |
| Operator Name | |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | |
| Operator City | |
| Operator State | |
| Operator Country | |
| Operator Zip code | |
| Operator Code | |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | Public Use |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | PWA |
| Departure City | |
| Departure State | |
| Departure Country | |
| Departure Time | 1400 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | |
| Destination City | |
| Destination State | |
| Destination Country | |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 2 2001 10:30AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |