McDonnell Douglas 520N N520NT
28 September 1994 · Mesa, Arizona, United States · Fatal
Summary
On 28 September 1994 at about 03:43 local time, a McDonnell Douglas 520N registered N520NT was involved in an accident near Mesa, Arizona, United States. 4 people were on board and one died, one was seriously injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.
The record
- Date
- at 03:43
- Classification
- Accident
- Location
- Mesa, Arizona, United States
- Nearest airport
- McDonnell Douglas Helipor (AZ81)
- Coordinates
- 33.4295, -111.7107
- Aircraft
- McDonnell Douglas 520N
- Registration
- N520NT
- Category
- Helicopter
- Engines
- 1
- Operator
- Not recorded
- Operating rule
- Part 91: General Aviation
- Purpose of flight
- Aerial Observation
- Phase of flight
- Not recorded
- Route
- Chandler → Unknown
- Aircraft damage
- Destroyed
- Weather
- VMC
- Light
- Night/Dark
- NTSB number
- LAX94FA383
People
1 person died.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 4 | 1 | 1 | 0 | 2 |
Probable cause
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.
Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.
Read the full NTSB narrative
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.
Quoted verbatim from the NTSB record.
Aircraft involved
| Aircraft | Registration | Operator | Damage |
|---|---|---|---|
| McDonnell Douglas 520N 520N | N520NT | - | Destroyed |
| McDonnell Douglas AH-64D AH-64D | R0324 | McDonnell Douglas Helicopter | Substantial |
Other McDonnell Douglas 520 accidents
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 20 May 1998 | McDonnell Douglas 520N | Lanai City, Maui, Hawaii, United States | - | Minor injuries | - |
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 16 Sep 1994 | Cessna 210L | Payson, Arizona, United States | Dairy Queen of S. Arizona, Inc | No injuries | - |
| 21 Sep 1994 | James B Edwards COZY | Skull Valley, Arizona, United States | - | Fatal | 1 |
| 21 Sep 1994 | Robinson R-22 | Benson, Arizona, United States | Same AS Registered Owner | No injuries | - |
| 1 Jul 1994 | Bell 206-B3 | Tucson, Arizona, United States | U.s. Forest Service | Unknown | - |
| 4 Jan 1994 | Bell 206B | Coolidge Dam, Arizona, United States | Southwest Helicopters, Inc. | Fatal | 1 |
| 15 Nov 1994 | Cessna 172K | Springerville, Arizona, United States | - | Fatal | 3 |