# NTSB SEA88FA069: Aero Commander 680FL, N291NC, Soda Springs, ID, April 9, 1988

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: April 8, 1988, 21:25 local (Apr 9, 1988, 03:25 UTC)
- Place: Soda Springs, ID
- Coordinates: 42.750812, -111.530967 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.7508&lon=-111.5310&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report July 3, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 40720
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA88FA069
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40720/pdf
- Page: https://openairdocs.org/ntsb/SEA88FA069

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, descent
  - light condition - dark night (contributing factor)
  - weather condition - snow (contributing factor)
  - weather condition - thunderstorm (contributing factor)
  - weather condition - turbulence (contributing factor)
  - design stress limits of aircraft - exceeded, pilot in command (cause)
  - wing - overload
  - wing - separation
  - horizontal stabilizer surface - overload
  - horizontal stabilizer surface - separation
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

WHILE EN ROUTE ON A NIGHT IFR CARGO FLT, THE PLT REQD & WAS CLRD FOR A DSCNT FROM AN IFR CRUISE ALT OF 16,000 FT TO PROCEED VFR-ON-TOP. THE LAST TRANSMISSION FROM THE ACFT WAS AT 2106 WHEN THE PLT ACKNOWLEDGED THAT HE WAS FAMILIAR WITH THE TERRAIN ALONG THE ROUTE. AT 2121:51 MDT, RADAR CONTACT WAS LOST AFTER THE ACFT MADE AN APRX 360 DEGREE LEFT TURN & DESCENDED THRU 13,800'. SHORTLY AFTER THAT, THE CONTROLLER TRIED TO CALL THE PLT TO INFORM HIM THAT RADAR CONTACT WAS LOST, BUT WAS UNABLE TO MAKE RADIO CONTACT. LATER, WRECKAGE OF THE ACFT WAS FOUND WHERE IT HAD CRASHED ABOUT 2 MI SW OF WERE RADAR CONTACT WAS LOST. THE WRECKAGE WAS SCATTERED OVER AN AREA OF MORE THAN ONE MILE. AN INVESTIGATION REVEALED THE LEFT WING & RGT HORIZONTAL STABILIZER HAD SEPD UPWARD FROM OVERLOAD. NO PRE-ACDNT FATIGUE OR PART FAILURE/MALFUNCTION WAS FND. WX RPRTS & PIREPS INDCD MODERATE TURBC & TOWERING CUMULUS CLOUDS IN THE AREA. APRX 60 MI WEST AT POCATELLO, ID, SNOW SHOWERS WERE RPRTD; 2 TO 3 INCHES OF SNOW FELL ON THE WRECKAGE OVERNIGHT.

## Aircraft

- Registration: [N291NC](https://openairdocs.org/deregistered/N291NC-1988-12-15), registration cancelled 1988-12-15, S/N 146186 (OpenAirDocs)
- Reported make and model: AERO COMMANDER 680FL
- Registry model: [Aero Commander 680FL](https://openairdocs.org/model/aero-commander-680fl) (registry code 0141608) (OpenAirDocs)
- Category: Airplane
- Serial number: 1461 86
- Airframe hours: 11873
- Engines: LYCOMING IO-720-B1B 400 horsepower reciprocating
- Damage: Destroyed
- Flight: Part 135
- Registered owner: Inter American Leasing
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, March 16, 1988, 18 hours before
- Departed: BIL, BILLINGS, MT
- Destination: SLC, SALT LAKE CITY, UT
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 5,013 total, 50 in this make and model, 157 in the last 90 days, 34 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Night/dark
- Temperature: 36 °F, dew point 25 °F
- Altimeter: 30.00 inHg
- Observed at: PIH, 60 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19880408048959A](https://openairdocs.org/incident/19880408048959A), Apr 8, 1988: Gulstm STC680, Soda Springs, ID, Destroyed, 2 fatal. High speed impact on a mountain slope. Storm cells turbulence and snow showers in area. Exact cause undetermined.

## Other investigations on N291NC (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB DEN79FA050](https://openairdocs.org/ntsb/DEN79FA050), Jul 19, 1979: Aero Comdr 680FL (N291NC), Northglenn, CO, substantial damage

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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