# NTSB SEA89LA127: Piper PA-28-180, N56759, Snoqualmie Pass, WA, June 30, 1989

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: June 30, 1989, 11:55 local (18:55 UTC)
- Place: Snoqualmie Pass, WA
- Coordinates: 47.419311, -121.369445 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.4193&lon=-121.3694&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious, 1 uninjured
- Status: Completed, report June 16, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41043
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA89LA127
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41043/pdf
- Page: https://openairdocs.org/ntsb/SEA89LA127

## Probable cause

IMPROPER IN-FLIGHT PLANNING/DESCISION BY THE PILOT, WHICH RESULTED IN THE AIRCRAFT ENTERING A BOX CANYON WITH INSUFFICIENT SPEED AND ALTITUDE TO MANEUVER OUT OF THE CONFINED AREA. FACTORS RELATED TO THE ACCIDENT WERE:  THE PILOT'S CONTINUED FLIGHT INTO KNOWN ADVERSE WEATHER CONDITIONS AND THE TERRAIN AND WEATHER CONDITIONS.

## Sequence of events

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

- In flight encounter with weather, maneuvering
  - weather condition - high terrain (contributing factor)
  - weather condition - clouds (contributing factor)
  - weather condition - low ceiling (contributing factor)
  - weather condition - rain (contributing factor)
  - flight into known adverse weather - continued, pilot in command (contributing factor)
- In flight collision with object, maneuvering - turn to reverse direction
  - terrain condition - blind/box canyon (contributing factor)
  - in-flight planning/decision - improper, pilot in command (cause)
  - maneuver - initiated, pilot in command
  - altitude - inadequate, pilot in command (cause)
  - airspeed - inadequate (cause)
  - stall/mush
  - object - tree(s)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

WHILE ATTEMPTING TO CROSS OVER THE CASCADE MOUNTAINS, THE PILOT ENCOUNTERED CLOUDS, WHICH THE ACFT WOULD NOT BE ABLE TO OUTCLIMB.  HE ELECTED TO DESCEND BELOW THE CLOUDS & FOLLOW AN INTERSTATE HIGHWAY THROUGH A PASS.  HE INADVERTENTLY ENTERED A BOX CANYON.  WHILE MANEUVERING TO REVERSE COURSE, THE AIRCRAFT MUSHED INTO TREES.  THE PILOT HAD RECEIVED A PREFLIGHT WEATHER BRIEFING, WHICH INDICATED VFR FLT CONDITIONS IN THE PASS.  A WEATHER OBSERVATION STATION (THAT WAS PREVIOUSLY IN THE PASS) HAD BEEN CLOSED BY THE NATIONAL WEATHER SERVICE.

## Aircraft

- Registration: [N56759](https://openairdocs.org/deregistered/N56759-1989-07-29), registration cancelled 1989-07-29, S/N 287405030 (OpenAirDocs)
- Reported make and model: PIPER PA-28-180
- Registry model: [Piper PA-28-180](https://openairdocs.org/model/piper-pa-28-180) (registry code 7102808) (OpenAirDocs)
- Category: Airplane
- Serial number: 28-7405030
- Airframe hours: 3743
- Engines: LYCOMING O-360-A4A 180 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Airways Sheetmetal, Inc.
- Registered owner: Airways Sheetmetal, Inc
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 10, 1989, 20 hours before
- Departed: GEG, SPOKANE, WA
- Destination: YCD, NANAIMO
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 93 total, 93 in this make and model, 56 as pilot in command, 24 in the last 90 days, 3 in the last 30 days

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 230° at 11 knots
- Visibility: 15 statute miles
- Temperature: 66 °F, dew point 46 °F
- Altimeter: 29.00 inHg
- Observed at: RNT, 31 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 19890630019019A](https://openairdocs.org/incident/19890630019019A), Jun 30, 1989: Piper PA28180, Snoqualmie Pass, WA, Destroyed. Wrong turn into box canyon following road through Pass as clouds lowered. Stalled into trees. Ats had advised was VMC

## Other investigations on N56759 (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 SEA78DYK05](https://openairdocs.org/ntsb/SEA78DYK05), Dec 23, 1977: Piper PA-28 (N56759), Agness, OR, 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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