Amateur-built EXEC-90 accident near Chandler, Arizona, December 8, 1993
On December 8, 1993 at about 3:00 pm local time, a amateur-built EXEC-90 (helicopter), registered N89678, was substantially damaged in an accident near Chandler, Arizona (Stellar Airpark airport). It was an instructional flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE FLIGHT INSTRUCTOR'S FAILURE TO PROPERLY FOLLOW THE AIRCRAFT BALLASTING PROCEDURES THAT RESULTED IN A LOSS OF CONTROL WHEN THE HELICOPTER'S CENTER OF GRAVITY LIMITS WERE EXCEEDED. INADEQUATE SUPERVISION OF THE TRAINING FLIGHT WAS A FACTOR IN THE ACCIDENT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 8, 1993 · about 3:00 pm local time
- Place
- Chandler, Arizona · Stellar Airpark · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built EXEC-90
- Registration
- N89678 · no longer on the register · serial RI-5023
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
A FLIGHT INSTRUCTOR WAS PROVIDING HELICOPTER INSTRUCTION TO A SECOND PILOT IN AN EXPERIMENTAL AIRCRAFT. A MOVEABLE BALLAST WEIGHT IS UTILIZED ON THE HELICOPTER TO ASSURE THAT THE CENTER OF GRAVITY LIMITS ARE NOT EXCEEDED. THE BALLAST WEIGHT IS POSITIONED ALONG THE CENTERLINE OF THE AIRCRAFT WHEN IT IS OCCUPIED BY TWO PERSONS. THE WEIGHT IS POSITIONED ON THE RIGHT LANDING GEAR SKID TUBE WHEN THE HELICOPTER IS OCCUPIED BY ONLY ONE PERSON. AFTER COMPLETING SOLO HOVER MANEUVERS, THE INSTRUCTOR BOARDED THE HELICOPTER AND INSTRUCTED THE STUDENT TO FLY BACK TO A COMPANY BUILDING. THE BALLAST WEIGHT WAS STILL POSITIONED ON THE RIGHT SKID. AFTER TAKEOFF WITH THE TWO OCCUPANTS, THE HELICOPTER PITCHED NOSE DOWN. THE NOSE AND MAIN ROTOR BLADES STRUCK THE GROUND AND THE HELICOPTER ROLLED OVER.
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 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 1,942 hours in all; 212 in this make and model; 101 in the last 90 days; 33 in the last 30 days; 1,719 as pilot in command; 977 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 217 hours
- Last inspection: continuous airworthiness programme, March 31, 1993; 217 hours since
- Maximum gross weight: 1,425 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway R-162 (piston); 0 hours total
- Operator: Cobb International INC.
The flight
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 120° at 5 knots
- Visibility: 45 statute miles
- Sky: broken clouds at 25,000 ft; not recorded at 25,000 ft
- Temperature: 54°F (12°C), dew point 30°F (-1°C)
- Altimeter: 30.00 inHg
- Observation at 3:50 pm from PHX, 10 miles away
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.
Other NTSB records under N89678 the same tail number, which may have belonged to a different aircraft at the time
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.