Aerospatiale AS350D accident near Los Angeles, California, April 7, 1997
On April 7, 1997 at about 7:09 pm local time, a Aerospatiale AS350D (helicopter), registered N317LT, was substantially damaged in an accident near Los Angeles, California (Transamerica Bldg Helipad airport). It was a positioning flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
the pilot's failure to ensure that the collective lock was properly seated before deplaning.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 7, 1997 · about 7:09 pm local time
- Place
- Los Angeles, California · Transamerica Bldg Helipad · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale AS350D · all AS350Ds on the register
- Registration
- N317LT · no longer on the register · serial 1403
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot exited the helicopter to escort a deplaning passenger. The student pilot rated passenger was left sitting in the helicopter with instructions not to touch the controls. While the pilot was standing nearby, the helicopter began bouncing up and down in a resonant mode. The pilot ran back to the helicopter and pulled the fuel flow control lever into the cut-off position. The helicopter yawed to the right and settled back on the deck. Investigation revealed the full down position of the collective was spring loaded to keep tension against the control lock. An inspection of the helicopter revealed that the collective was not down and locked, nor were the frictions tightly applied. The manufacturer reported instances in which the collective lock was not seated properly, and consequently, the collective became released while the engine was running. If the lock slips off collective, the spring's tension could force the control to move upward. No malfunction or failure was found with the engine or rotor systems.
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: airline transport pilot, flight instructor
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 6,582 hours in all; 300 in this make and model; 272 in the last 90 days; 95 in the last 30 days; 6,466 as pilot in command; 5,323 on instruments
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 9,051 hours
- Last inspection: 100-hour inspection, February 28, 1997; 18 hours since
- Maximum gross weight: 4,300 lb
- Seats: 6
- Landing gear: fixed
- Engine: Lycoming LTS-101-600A (turboshaft); 0 hours total
The flight
- Departed from: Uc San Diego CA at 6:00 pm
- Destination: 63L
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 210° at 6 knots
- Visibility: 9 statute miles
- Sky: scat at 25,000 ft
- Temperature: 57°F (14°C), dew point 54°F (12°C)
- Altimeter: 30.00 inHg
- Observation at 6:53 pm from LAX, 12 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 |
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.