Trenton Mercer Airport
Aircraft Accident/Incident Report

Trenton, New Jersey 08628
Saturday, December 9, 2000 11:00 EST

NTSB Narrative Summary Released at Completion of Accident

With a fight instructor, the pilot executed a normal takeoff from Runway 34 for right closed traffic. Because a UH-60 helicopter was executing an approach from the southwest to the threshold of Runway 34, the pilot extend the touchdown point by 1,000 feet. The helicopter transitioned to hovering flight near the threshold, about 30 seconds before the accident airplane. After a short delay, the UH-60 air-taxied to the ramp. When the accident airplane was about 20 feet above the ground, it suddenly rolled right, (faster than a full application of aileron could counteract,) and the right wing contacted the ground. Witness statements place the UH-60, 100 to 600 feet away from the accident airplane at the time of the accident. According to the Aeronautical Information Manual, every aircraft generates vortices, that can cause an uncommanded roll that exceeds the roll-control authority of the encountering airplane. Landing helicopters produce a pair of strong, high-speed trailing vortices similar to larger fixed wing aircraft. Pilots of small aircraft should use caution when operating behind landing helicopters.

NTSB Probable Cause Narrative

The flight instructor's improper decision to allow his student to land in close proximity to a hovering helicopter.

Event Information

Type of Event Accident
Event Date 12/9/2000
Event Day of the Week Saturday
Time of Event 1100
Event Time Zone Eastern Standard Time
Event City TRENTON
Event State NEW JERSEY
Event Country --
Zipcode of the event site 08628
Event Date Year 2000
Event Date Month 12
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport TRENTON MERCER
Event Location Nearest Airport ID TTN
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 213
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1053 Eastern Standard Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID TTN
Elevation of weather observation facility 213
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation EST
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) 10
Air Temperature at event time (in degrees celsius) 1
Dew Point at event time (in degress fahrenheit) -9
Wind Direction (degrees magnetic) 320
Variable Wind Indicator Unknown
Wind Speed (knots) 10
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
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) 1061
NTSB Notification Source Eastern Region Comm Center
NTSB Notification Date Dec 9 2000 12:00AM
NTSB Notification Time 1600
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Jul 2 2001 3:52PM
User who most recently changed record MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N201MP
NTSB Number NYC01LA057
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 Mooney
Aircraft Model M-20J
Aircraft Series Identifier M-20J
Aircraft Serial Number 24-0072
Certified Max Gross Weight 2740
Aircraft Category Airplane
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 4
Number of Engines 1
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Annual
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name ROBERT KEEFER
Aircraft Owner Street Address
Aircraft Owner City YARDLEY
Aircraft Owner State PA
Aircraft Owner Country
Aircraft Owner Zipcode 19067
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) Instructional
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code TTN
Departure City TRENTON
Departure State NJ
Departure Country
Departure Time 1045
Departure Time Zone EST
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 Jun 2 2001 4:09AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 34
Runway Length 4800
Runway Width 150
Sight Seeing flight No
Air Medical Flight No
Medical Flight --