Aerospatiale AS350B incident near Grand Canyon Pk, Arizona, February 1, 1999
On February 1, 1999 at about 5:10 pm local time, a Aerospatiale AS350B (helicopter), registered N32GA, suffered minor damage in an incident near Grand Canyon Pk, Arizona. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). No one was hurt; 7 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The in-flight separation of a side window for undetermined reasons.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 1, 1999 · about 5:10 pm local time
- Place
- Grand Canyon Pk, Arizona · map
- Type
- Incident
- Injuries
- No one was hurt; 7 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale AS350B · all AS350Bs on the register
- Registration
- N32GA · registry record · serial 1188
- Damage
- Minor damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
While descending on an aerial tour flight with six passengers, the left side bubble window separated from the helicopter and impacted a tail rotor blade. The pilot made a precautionary landing in the canyon without further incident. Neither the separated window nor its doorframe attachment seal (gasket) was recovered. Examination of the helicopter's tail rotor blade found it bent and scratched with areas of debonded material. The damaged blade was not repairable. During preflight inspection the pilot did not see any damage to the window, and during the flight the left seated passenger was not observed pressing on it. Due to observed cracks in the previous window 4.5 months and 589 flight hours earlier, it had been replaced with a window removed from another helicopter. No maintenance record entry was found for the window installation. The operator's replacement window was manufactured under a FAA Supplemental Type Certificate. The STC holder said that if its 'wedge' window is not properly installed, or if it becomes cracked or damaged due to exposure to harmful cleaning solvents, its integrity may be compromised. The operator reported that if a small crack existed near the window's edge, it may not have been noticed/reported by the pilot due to a lack of conspicuity. The reason(s) for the window separation could not be determined.
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: commercial pilot
- Ratings: multi-engine land; single-engine land; rotorcraft: helicopter
- Flight time: 781 hours in all
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 9,743 hours
- Last inspection: annual inspection, August 21, 1998; 589 hours since
- Maximum gross weight: 4,300 lb
- Seats: 7
- Landing gear: fixed
- Engine: Turbomeca ARRIEL 1B (turboshaft); 0 hours total
- Operator: Silverado Helicopters, INC.
The flight
- Departed from: LAS Las Vegas NV at 4:28 pm
- Destination: GCN Grand Canyon AZ
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 340° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 36°F (2°C), dew point 23°F (-5°C)
- Altimeter: 30.00 inHg
- Observation at 4:54 pm from IGM, 45 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 6 |
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.