Cobb International Rotorway Exec 90 accident near Casa Grande, Arizona, February 5, 2003
On February 5, 2003 at about 3:15 pm local time, a Cobb International Rotorway Exec 90 (helicopter), registered N9876D, was substantially damaged in an accident near Casa Grande, Arizona (Phoenix Regional 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 maintain directional control of the helicopter during the flare and landing. Factors in the accident were the failure of the secondary drive shaft and inadequate tail rotor failure procedures specified by the manufacturer.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 5, 2003 · about 3:15 pm local time
- Place
- Casa Grande, Arizona · Phoenix Regional · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Cobb International Rotorway Exec 90
- Registration
- N9876D · no longer on the register · serial 5160
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The helicopter made a hard landing following a failure of the antitorque system. While in the landing pattern, the student and CFI heard a "bang." The CFI took the flight controls, initiated an autorotation, and turned to an open area for an emergency landing. During the autorotation the CFI noticed a loss of his ability to maintain directional control. He lowered the collective and continued with the autorotation. As he pulled collective to cushion the landing the helicopter yawed to the left, landed firmly on the ground, and rolled over on to its right side. The CFI's execution of an autorotative landing failed to adjust for the engagement of the engine when he pulled in collective to cushion the landing. Engagement of engine power in the autorotative flare caused the helicopter to yaw left, which was not compensated for by the failed tail rotor. The helicopter encountered ground resistance when it landed, and the force of the uncontrolled left yaw rolled it over onto its right side. The FAA Rotorcraft Flying Handbook describes the appropriate response to an antitorque failure as an entry into an autorotation profile by reducing the collective and rolling off the throttle. Rolling off the throttle will prevent the engine from engaging during the autorotative landing. The manufacturer's flight manual does not address the issue of performing an autorotative landing with a tail rotor failure. Examination of the helicopter revealed that the secondary drive shaft appeared to have fractured between the lower bearing and the lock collar. Examination of the shaft revealed fretting and corrosion in the area contacted by the lock collar. The fracture was a result of fatigue cracking that initiated in the area of fretting and corrosion. This secondary drive shaft had been involved in one helicopter rollover and two tail rotor strikes. It is possible that excessive loads generated during these previous events was sufficient to loosen the lower bearing on the shaft and initiate the fretting and corrosion process that eventually led to the initiation of a fatigue crack.
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
Flight instructor
- Certificate: flight instructor, commercial pilot, private
- Ratings: single-engine land; instructor: helicopter; instructor: instrument helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,900 hours in all; 1,100 in this make and model; 1,800 as pilot in command
- Last flight review: July 1, 2002
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
- Injury: minor injuries
Dual student
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 860 hours in all; 21 in this make and model; 34 in the last 90 days; 28 in the last 30 days; 765 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 364 hours
- Last inspection: continuous airworthiness programme, December 3, 2002; 12 hours since
- Maximum gross weight: 1,425 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway 162 (piston); 0 hours total
The flight
- Departed from: P19 Chandler AZ at 2:55 pm
- Destination: A39 Casa Grande AZ
- Flight plan: none
- Runway 03, 4,000 ft by 50 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 090° at 5 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 25,000 ft; clear
- Temperature: 61°F (16°C), dew point 39°F (4°C)
- Altimeter: 30.10 inHg
- Observation at 2:45 pm from CHD, 19 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 N9876D 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.