Individually Owned: 150,657
Corporate Owned: 137,281
Brooks Field Airport
Aircraft Accident/Incident Report
Marshall, Michigan 49068
Sunday, August 21, 2011 18:00 EDT
NTSB Narrative Summary Released at Completion of Accident
The accident occurred during a glider tow operation. The glider pilot reported experiencing some turbulence during initial climb, followed by a high intensity thermal. The glider pilot lost sight of the airplane (towplane) briefly then relocated it below and to the right of the glider. He released from the towplane and landed without further incident. The glider pilot noted that the towplane appeared to be in stable flight at the time of the release. A witness stated that the takeoff appeared to be normal, but the towplane and glider encountered some turbulence near the end of the runway. He commented that the glider pilot appeared to be having some difficulty staying in position behind the towplane. At one point, the glider was subjected to a tugging motion, which appeared to be due to slack being taken out of the tow rope. The glider subsequently separated from the towplane. The towplane turned right, while the glider continued straight ahead briefly. The towplane was about 350 feet above ground level when the right wing dropped and it entered a 60- to 70-degree nose-down attitude. The towplane completed about one-half of a rotation before the witness lost sight of it behind trees. The towplane impacted an open field about 1/2 mile west of the departure end of the runway. A postaccident examination of the towplane did not reveal any anomalies consistent with a preimpact failure or malfunction. It is likely that, when the glider pilot allowed the glider to climb above the towplane to the extent that he lost sight of the towplane, the resulting tension on the tow rope reduced the towplane pilot's control authority. The resulting loss of airspeed subsequently induced an aerodynamic stall. Although the glider and the towplane separated, there was not enough altitude for the towplane pilot to recover from the upset before the towplane impacted the ground.
NTSB Probable Cause Narrative
The towplane pilot's loss of control during an aerotow operation due to the glider pilot's inability to maintain a proper position behind the towplane while encountering turbulence on initial climb.
Event Information
| Type of Event | Accident |
| Event Date | 8/21/2011 |
| Event Day of the Week | Sunday |
| Time of Event | 1800 |
| Event Time Zone | Eastern Daylight Time |
| Event City | Marshall |
| Event State | MICHIGAN |
| Event Country | -- |
| Zipcode of the event site | 49068 |
| Event Date Year | 2011 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 421504N |
| Event Location Longitude | 0845720W |
| Event Location Airport | Brooks Field |
| Event Location Nearest Airport ID | RMY |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 1 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 941 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1800 Eastern Daylight Time |
| Direction of event from weather observation facility (degrees) | 90 |
| Weather Observation Facility ID | RMY |
| Elevation of weather observation facility | 941 |
| Distance of event from weather observation facility (units?) | 1 |
| Time Zone of the weather observation | EDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 5500 |
| Sky/Lowest/Cloud Conditions | Scattered |
| 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) | 23 |
| Dew Point at event time (in degress fahrenheit) | 12 |
| Wind Direction (degrees magnetic) | 280 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 14 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 19 |
| Altimeter Setting at event time (in. Hg) | 29.94 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Fatal |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | 1 |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 29831 |
| NTSB Notification Source | FAA-AGL ROC |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | May 17 2012 1:21PM |
| User who most recently changed record | snyg |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N7638V |
| NTSB Number | CEN11LA585 |
| Missing Aircraft Indicator | -- |
| 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 | AERO COMMANDER |
| Aircraft Model | CALLAIR A-9B |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 1366 |
| Certified Max Gross Weight | 3000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 1 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Jun 26 2011 12:00AM |
| Airframe hours since last inspection | 27 |
| Airframe Hours | 6833 |
| ELT Installed | No |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | MARSHALL SOARING CLUB INC |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | MARSHALL |
| Aircraft Owner State | MI |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 49068-0944 |
| Operator is an individual? | No |
| Operator Name | MARSHALL SOARING CLUB INC |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | MARSHALL |
| Operator State | MI |
| Operator Country | USA |
| Operator Zip code | 49068-0944 |
| 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 | -- |
| 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) | Glider Tow |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | RMY |
| Departure City | Marshall |
| Departure State | MI |
| Departure Country | USA |
| Departure Time | 1758 |
| Departure Time Zone | EDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | RMY |
| Destination City | Marshall |
| Destination State | MI |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Mar 21 2012 10:36AM |
| User who most recently changed record | sort |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | 28 |
| Runway Length | 3500 |
| Runway Width | 100 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |