Quad City Ultralight Aircraft Challenger LSS accident near Moses Lake, Washington, May 31, 2008
On May 31, 2008 at about 6:15 pm local time, a Quad City Ultralight Aircraft Challenger LSS, an amateur-built aircraft,, registered N95478, was substantially damaged in an accident during approach (VFR pattern downwind) near Moses Lake, Washington (Moses Lake Municipal Airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's inability to maintain control due to an in-flight separation of the vertical fin as a result of the failure of the airplane's builder to properly secure the vertical fin to the fuselage.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 31, 2008 · about 6:15 pm local time
- Place
- Moses Lake, Washington · Moses Lake Municipal Airport · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Quad City Ultralight Aircraft Challenger LSS, amateur-built
- Registration
- N95478 · no longer on the register · serial CH2-1106-LSS-0107
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was completing a local flight and entered the downwind leg of the traffic pattern at the destination airport. As the airplane was on the downwind leg and almost abeam the runway identifier numbers, the engine power reduced and the nose pitched up about 15 degrees. The airplane made a tight turn onto the base leg and then overshot final approach. The airplane was high and appeared to be configured in a slip (right wing low) while approaching the runway. When reaching about 30 feet above ground level (agl), the airplane pitched nose high, as if the pilot was attempting to flare. The engine power slowly increased and the airplane turned about 45 degrees, barely clearing a hangar and power lines. The airplane made numerous erratic maneuvers while varying altitudes between 45 and 300 feet agl. It then pitched up about 65 degrees nose high and made a left bank. It subsequently stalled and continued in a spin about 360 degrees before impacting a field located adjacent to the runway. A postaccident examination revealed that the vertical fin had separated from the fuselage attach points and remained attached to the airplane only by the horizontal tail plane struts, the elevator control push rods, and the rudder cables. Examination revealed that the vertical fin attach tubes (forward and aft) had not been secured to the fuselage attach tubing. The bolts designed to secure the vertical fin to the fuselage were not attached; rather, the bolts were secured to the fuselage tubing and the undrilled vertical fin attach tubing was resting on top of the bolts. The build manual for the airplane states that during assembly, the builder must remove the bolts secured to the fuselage attach tubing and insert the vertical fin attach tubing. Following insertion the builder is instructed to drill the vertical fin tubing and secure the bolt through both pieces of tubing.
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
What happened, in order
- Flight control sys malf/fail during approach (VFR pattern downwind) defining event
- Loss of control in flight during approach (VFR pattern downwind)
The NTSB's findings
- cause Personnel issues › Task performance › Maintenance › Installation › Other/unknown
- cause Aircraft › Aircraft structures › Empennage structure › Vertical stabilizer › Incorrect service/maintenance
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › (general) › Attain/maintain not possible
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane
- Flight time: 10 in this make and model
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: frt
- Injury: fatal
The aircraft
- Last inspection: inspection type not recorded
- Landing gear: fixed
- Engine: Rotax 582 (piston); 0 hours total
The flight
- Departed from: W20 Moses Lake WA at 4:45 pm
- Destination: W20
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 210° at 3 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 73°F (23°C), dew point 41°F (5°C)
- Altimeter: 30.02 inHg
- Observation at 10:52 am from MWH, 5 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 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.
Other NTSB records under N95478 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.