Individually Owned: 150,657
Corporate Owned: 137,281
Chickasha Municipal Airport
Aircraft Accident/Incident Report
Chickasha, Oklahoma 73018
Monday, April 11, 2011 10:15 CDT
NTSB Narrative Summary Released at Completion of Accident
The certified flight instructor (CFI) reported that the airplane was on a downwind leg for landing when a pilot-rated passenger who was sitting in the cabin told him that the right aileron was partially separated from the airplane. The CFI took control of the airplane and landed it uneventfully. The post incident inspection of the airplane revealed that the two inboard aileron hinges were separated from the airframe. The screws (8 screws, 4 upper, 4 lower) which attached the aileron to the aileron hinge points were seated in the aileron skin, but did not screw into the corresponding nut plates on the aileron hinge points. The aileron was not damaged so a mechanic attached the aileron properly to the aileron hinge points and the airplane was returned to service. Maintenance records indicated that the airplane had undergone a phase inspection 10 days prior to the incident. During the phase inspection, the right aileron was removed to repair some light surface corrosion and was reinstalled on the airplane. The incident occurred 5.3 hours after the phase inspection was performed. Eight years prior to the accident, the aircraft manufacturer issued a communique which stated that their technical support department had received reports that during aileron installation, screws missed the nut plates on the aileron hinge points. It stated that this condition can go unnoticed.
NTSB Probable Cause Narrative
The mechanic's improper installation of the aileron.
Event Information
| Type of Event | Incident |
| Event Date | 4/11/2011 |
| Event Day of the Week | Monday |
| Time of Event | 1015 |
| Event Time Zone | Central Daylight Time |
| Event City | Chickasha |
| Event State | OKLAHOMA |
| Event Country | -- |
| Zipcode of the event site | 73018 |
| Event Date Year | 2011 |
| Event Date Month | 4 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 350550N |
| Event Location Longitude | 0975803W |
| Event Location Airport | Chickasha Municipal Airport |
| Event Location Nearest Airport ID | CHK |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | 1 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 1152 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1000 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | CHK |
| Elevation of weather observation facility | 1152 |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | CDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | -- |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 22 |
| Dew Point at event time (in degress fahrenheit) | 7 |
| Wind Direction (degrees magnetic) | 340 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 19 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 29 |
| Altimeter Setting at event time (in. Hg) | 30.07 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 4 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 28437 |
| NTSB Notification Source | FAA-SWA-ROC |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jul 8 2011 8:16AM |
| User who most recently changed record | johb |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N37OU |
| NTSB Number | CEN11IA280 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BEECH |
| Aircraft Model | 90B |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | LJ-1428 |
| Certified Max Gross Weight | 10100 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 8 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | Apr 1 2011 12:00AM |
| Airframe hours since last inspection | 5 |
| Airframe Hours | 2789 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | Board of Regents, University of Oklahoma |
| Aircraft Owner Street Address | 1700 Lexington |
| Aircraft Owner City | Norman |
| Aircraft Owner State | OK |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 73069 |
| Operator is an individual? | No |
| Operator Name | University of Oklahoma, Dept of Aviation |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | 1700 Lexington |
| Operator City | Norman |
| Operator State | OK |
| Operator Country | USA |
| Operator Zip code | 73069 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | GD8S160Q |
| 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) | Instructional |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | OUN |
| Departure City | Norman |
| Departure State | OK |
| Departure Country | USA |
| Departure Time | 915 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | OUN |
| Destination City | Norman |
| Destination State | OK |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | May 2 2011 1:14PM |
| User who most recently changed record | scoa |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | 35 |
| Runway Length | 5101 |
| Runway Width | 100 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |