Amateur-built LANCAIR IV P and Yakovlev YAK-55M mid-air collision near Hammonton, New Jersey, August 20, 2011
On August 20, 2011 at about 5:15 pm local time, 2 aircraft, amateur-built LANCAIR IV P (N71DM) and Yakovlev YAK-55M (N521BC), were involved in a mid-air collision near Hammonton, New Jersey (Hammonton airport). 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The Lancair pilot's failure to see and avoid the aerobatic airplane. Contributing to the accident was the Lancair pilot's inadequate use of collision avoidance strategies while inbound to an area of known potential aerobatic activity.
The Lancair pilot's failure to see and avoid the aerobatic airplane. Contributing to the accident was the Lancair pilot's inadequate use of collision avoidance strategies while inbound to an area of known potential aerobatic activity.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 20, 2011 · about 5:15 pm local time
- Place
- Hammonton, New Jersey · Hammonton · map
- Type
- Accident · mid-air collision
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Amateur-built LANCAIR IV P
- Registration
- N71DM · registry record · serial LIV 387
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
- Aircraft 2
- Yakovlev YAK-55M · all YAK-55Ms on the register
- Registration
- N521BC · registry record · serial 961007
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative for the amateur-built LANCAIR IV P final · quoted from the NTSB record
The Lancair pilot told a witness that he was going to fly the high-performance airplane to a nearby airport to visit a friend. The pilot was aware that the nearby airport had occasional aerobatic activity near the runway, within an "aerobatic box." The box was active on the day of the accident, with a Notice to Airmen issued for aerobatic activity at 3,500 feet and below. The airplane approached the airport about 3,500 feet; however, the exact altitude could not be determined due to the fidelity of the radar/encoder data. As the airplane approached the airport at a high airspeed, likely about 190 knots, it collided with an aerobatic airplane that had just completed a hammerhead stall and was observed in a dive. The pilot's airplane cut through the aerobatic airplane's fuselage just aft of the cockpit, top to bottom, and lost about 4 feet of its left wing. The pilot's airplane then crashed into nearby woods, and the pilot of the aerobatic airplane parachuted into the same woods. The aerobatic pilot and an observer stated that clearing turns were conducted prior to the aerobatic maneuver. However, the sun’s position and the airspeed of the oncoming airplane would have made it highly unlikely that the aerobatic pilot would have seen it. It is unknown what the inbound pilot's intentions were at the time of the accident. A relative of the inbound pilot, another pilot who had flown with him often, surmised that the pilot's approach to the airport at such a high altitude may have been an exploratory overflight, which is supported by the airplane's high airspeed at the time. Radar indicated that the pilot's airplane did not perform any standoff maneuvering prior to approaching the airport, and other pilots in the air at the time heard no advisory radio transmissions from him. During flight in visual meteorological conditions, the tenets of "see and avoid" apply. With the inbound pilot's knowledge of potential aerobatic activity at the airport, it is not known why he did not use advocated collision avoidance strategies.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Yakovlev YAK-55M final · quoted from the NTSB record
The Lancair pilot told a witness that he was going to fly the high-performance airplane to a nearby airport to visit a friend. The pilot was aware that the nearby airport had occasional aerobatic activity near the runway, within an "aerobatic box." The box was active on the day of the accident, with a Notice to Airmen issued for aerobatic activity at 3,500 feet and below. The airplane approached the airport about 3,500 feet; however, the exact altitude could not be determined due to the fidelity of the radar/encoder data. As the airplane approached the airport at a high airspeed, likely about 190 knots, it collided with an aerobatic airplane that had just completed a hammerhead stall and was observed in a dive. The pilot's airplane cut through the aerobatic airplane's fuselage just aft of the cockpit, top to bottom, and lost about 4 feet of its left wing. The pilot's airplane then crashed into nearby woods, and the pilot of the aerobatic airplane parachuted into the same woods. The aerobatic pilot and an observer stated that clearing turns were conducted prior to the aerobatic maneuver. However, the sun’s position and the airspeed of the oncoming airplane would have made it highly unlikely that the aerobatic pilot would have seen it. It is unknown what the inbound pilot's intentions were at the time of the accident. A relative of the inbound pilot, another pilot who had flown with him often, surmised that the pilot's approach to the airport at such a high altitude may have been an exploratory overflight, which is supported by the airplane's high airspeed at the time. Radar indicated that the pilot's airplane did not perform any standoff maneuvering prior to approaching the airport, and other pilots in the air at the time heard no advisory radio transmissions from him. During flight in visual meteorological conditions, the tenets of "see and avoid" apply. With the inbound pilot's knowledge of potential aerobatic activity at the airport, it is not known why he did not use advocated collision avoidance strategies.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the amateur-built LANCAIR IV P from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during maneuvering defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
- factor Personnel issues › Action/decision › Action › Lack of action › Pilot
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 4,280 hours in all
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 441 hours
- Last inspection: condition inspection, October 13, 2010
- Maximum gross weight: 3,550 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental IO-550 (piston); 0 hours total
The flight
- Departed from: VAY Mount Holly NJ
- Destination: N81 Hammonton NJ
- Flight plan: none
- Runway 21, 3,601 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 150° at 9 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 8,500 ft
- Temperature: 82°F (28°C), dew point 64°F (18°C)
- Altimeter: 29.98 inHg
- Observation at 4:54 pm from ACY, 14 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
The factual record for the Yakovlev YAK-55M from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during maneuvering (aerobatics) defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot of other aircraft
- factor Personnel issues › Action/decision › Action › Lack of action › Pilot of other aircraft
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 610 hours in all; 260 in this make and model; 50 in the last 90 days; 13 in the last 30 days; 554 as pilot in command
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 430 hours
- Last inspection: annual inspection, March 10, 2011
- Maximum gross weight: 2,800 lb
- Seats: 1
- Landing gear: retractable
- Engine: Vendenyev M14P (piston); 0 hours total
The flight
- Departed from: N81 Hammonton NJ at 4:15 pm
- Destination: N81 Hammonton NJ
- Flight plan: none
- Runway 21, 3,601 ft by 75 ft
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.