Accidents · NTSB LAX94FA383 · Final report

Mcdonnell Douglas 520N and Mcdonnell Douglas AH-64D mid-air collision near Mesa, Arizona, September 28, 1994

On September 28, 1994 at about 3:43 am local time, 2 aircraft, Mcdonnell Douglas 520N (N520NT) and Mcdonnell Douglas AH-64D (R0324), were involved in a mid-air collision near Mesa, Arizona (Mcdonnell Douglas Helipor airport). 1 person was killed and 1 person was seriously injured; 2 others were unhurt. The weather was visual conditions (good weather).

The NTSB's probable cause their words, unchanged

FAILURE OF THE CHASE HELICOPTER PILOT TO MAINTAIN CLEARANCE FROM THE LEAD HELICOPTER DURING A NIGHT APPROACH TO LAND. POSSIBLE FACTORS RELATING TO THE ACCIDENT WERE: DARKNESS, AND INADEQUATE RADIO COORDINATION BETWEEN FLIGHT CREWS OF THE TWO HELICOPTERS.

Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.

What the record shows

Date: September 28, 1994 · about 3:43 am local time
Place: Mesa, Arizona · Mcdonnell Douglas Helipor · map
Type: Accident · mid-air collision
Injuries: 1 person was killed and 1 person was seriously injured; 2 others were unhurt.
Weather: visual conditions (good weather)
Aircraft 1: Mcdonnell Douglas 520N
Registration: N520NT · registry record · serial F-12
Damage: Destroyed
Flight: Aerial observation flight · general aviation rules (Part 91)
Aircraft 2: Mcdonnell Douglas AH-64D
Registration: R0324 · no longer on the register · serial PV270
Damage: Substantial damage
Flight: Flight of an unrecorded kind · general aviation rules (Part 91)

The NTSB's narrative for the Mcdonnell Douglas 520N final · quoted from the NTSB record

A TEST HELICOPTER (MCDONNELL DOUGLAS AH-64D, WITH 1 VHF RADIO) AND A CHASE HELICOPTER (MCDONNELL DOUGLAS 520N, WITH 2 VHF RADIOS) WERE ON A NIGHT VFR FLIGHT FROM CHANDLER, AZ, TO THE MCDONNELL DOUGLAS HELIPORT AT MESA, AZ. THE MISSION OF THE CHASE CREW (CHASE) WAS TO SURVEIL THE AREA FOR THE TEST CREW (LEAD) AND TO PROVIDE INFORMATION CONCERNING OTHER AIR TRAFFIC OR HAZARDS. THE DESTINATION HELIPORT WAS LOCATED JUST NORTH OF FALCON FIELD. DURING ARRIVAL, LEAD NOTIFIED CHASE OF A VHF FREQUENCY CHANGE TO THE FALCON FIELD TOWER (ATCT) FREQUENCY. CHASE ACKNOWLEDGED; THIS WAS THE LAST KNOWN TRANSMISSION FROM CHASE. LEAD THEN CHANGED TO THE HELIPORT'S 'APACHE RAMP CONTROL' FREQUENCY. THE GROUND CONTROL RADIO OPERATOR, MONITORING THE FREQUENCY, CLEARED THE HELICOPTER(S) TO LAND ON RUNWAY 22 AT THE HELIPORT. SOON THEREAFTER, THE CHASE HELICOPTER COLLIDED WITH THE LEAD HELICOPTER. DURING THE MIDAIR COLLISION, THE MAIN ROTOR BLADES OF CHASE STRUCK THE LEFT WING AND WING STORES OF LEAD. LEAD CONTINUED TO A SAFE LANDING, BUT THE MAIN ROTOR SEPARATED FROM THE CHASE HELICOPTER, AND IT CRASHED. AN INVESTIGATION REVEALED THE CHASE HELICOPTER HAD CONVERGED ON THE LEAD HELICOPTER FROM THE LEFT REAR QUADRANT. AN EXPLETIVE OF AN UNKNOWN SOURCE WAS TRANSMITTED ON THE ATCT FREQUENCY AT ABOUT THE TIME OF THE MIDAIR COLLISION. TESTS OF THE RADIOS FROM THE CHASE HELICOPTER REVEALED THEY WERE BOTH ON THE ATCT FREQUENCY.

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 Mcdonnell Douglas AH-64D final · quoted from the NTSB record

A TEST HELICOPTER (MCDONNELL DOUGLAS AH-64D, WITH 1 VHF RADIO) AND A CHASE HELICOPTER (MCDONNELL DOUGLAS 520N, WITH 2 VHF RADIOS) WERE ON A NIGHT VFR FLIGHT FROM CHANDLER, AZ, TO THE MCDONNELL DOUGLAS HELIPORT AT MESA, AZ. THE MISSION OF THE CHASE CREW (CHASE) WAS TO SURVEIL THE AREA FOR THE TEST CREW (LEAD) AND TO PROVIDE INFORMATION CONCERNING OTHER AIR TRAFFIC OR HAZARDS. THE DESTINATION HELIPORT WAS LOCATED JUST NORTH OF FALCON FIELD. DURING ARRIVAL, LEAD NOTIFIED CHASE OF A VHF FREQUENCY CHANGE TO THE FALCON FIELD TOWER (ATCT) FREQUENCY. CHASE ACKNOWLEDGED; THIS WAS THE LAST KNOWN TRANSMISSION FROM CHASE. LEAD THEN CHANGED TO THE HELIPORT'S 'APACHE RAMP CONTROL' FREQUENCY. THE GROUND CONTROL RADIO OPERATOR, MONITORING THE FREQUENCY, CLEARED THE HELICOPTER(S) TO LAND ON RUNWAY 22 AT THE HELIPORT. SOON THEREAFTER, THE CHASE HELICOPTER COLLIDED WITH THE LEAD HELICOPTER. DURING THE MIDAIR COLLISION, THE MAIN ROTOR BLADES OF CHASE STRUCK THE LEFT WING AND WING STORES OF LEAD. LEAD CONTINUED TO A SAFE LANDING, BUT THE MAIN ROTOR SEPARATED FROM THE CHASE HELICOPTER, AND IT CRASHED. AN INVESTIGATION REVEALED THE CHASE HELICOPTER HAD CONVERGED ON THE LEAD HELICOPTER FROM THE LEFT REAR QUADRANT. AN EXPLETIVE OF AN UNKNOWN SOURCE WAS TRANSMITTED ON THE ATCT FREQUENCY AT ABOUT THE TIME OF THE MIDAIR COLLISION. TESTS OF THE RADIOS FROM THE CHASE HELICOPTER REVEALED THEY WERE BOTH ON THE ATCT FREQUENCY.

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 Mcdonnell Douglas 520N from the NTSB's investigation tables, in plain English

Pilot

Certificate: airline transport pilot
Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: instrument airplane; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
Flight time: 17,795 hours in all; 1,550 in this make and model; 70 in the last 90 days; 30 in the last 30 days; 14,055 as pilot in command; 3,500 on instruments
Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
Seat: left

The aircraft

Airframe total time: 1,829 hours
Last inspection: 100-hour inspection, August 17, 1994; 28 hours since
Maximum gross weight: 3,350 lb
Seats: 4
Landing gear: fixed
Engine: Allison 250-C20R (turboshaft); 0 hours total

The flight

Departed from: IWA Chandler AZ at 3:28 am
Destination: AZ81 AZ
Runway 22, 1,650 ft by 100 ft

Weather at the time

Light: night, dark
Visibility: 10 statute miles
Sky: clear
Temperature: 84°F (29°C), dew point 52°F (11°C)
Altimeter: 29.00 inHg
Observation at 3:56 am from PHX, 14 miles away

Injuries

	Fatal	Serious	Minor	None
Crew	1
Passengers		1

The factual record for the Mcdonnell Douglas AH-64D from the NTSB's investigation tables, in plain English

Pilot

Certificate: commercial pilot
Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
Flight time: 8,239 hours in all; 3,066 in this make and model; 176 in the last 90 days; 4 in the last 30 days; 2,827 as pilot in command; 2,265 on instruments
Medical certificate: Class 2 (valid medical--no waivers/lim.)
Seat: frt

The aircraft

Airframe total time: 317 hours
Last inspection: continuous airworthiness programme, September 23, 1994; 8 hours since
Maximum gross weight: 23,000 lb
Seats: 2
Landing gear: fixed
Engine: Ge T700-7016 (turboshaft); 0 hours total

The flight

Departed from: IWA Chandler AZ
Destination: AZ81
Runway 22, 1,650 ft by 100 ft
A second pilot was aboard

Injuries

	Fatal	Serious	Minor	None
Crew				2

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.