Amateur-built SPACEWALKER II accident near Conroe, Texas, September 25, 1999
On September 25, 1999 at about 10:15 pm local time, a amateur-built SPACEWALKER II, registered N235FC, was destroyed in an accident near Conroe, Texas (Montgomery County airport). It was a personal flight under general aviation rules (Part 91). 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The in-flight separation of the left wing due to the failure of the wing spars resulting from the builder's improper design change utilizing basswood for the spars instead of the specified spruce.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 25, 1999 · about 10:15 pm local time
- Place
- Conroe, Texas · Montgomery County
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SPACEWALKER II SPACEWALKE
- Registration
- N235FC · no longer on the register · serial SW209FO16
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The homebuilt airplane (TT 114.3 hours & 22.4 hrs since last condition inspection) was destroyed following an in-flight separation of the left wing in level flight and the subsequent uncontrolled flight into terrain. The two-place (tandem) seating, open cockpit, low wing, fabric covered airplane incorporated a tubular steel welded fuselage and empennage, with wooden wings. The left wing separation points were at the wing root where the wooden main wing spar and rear wing spar passed through the tubular brackets of the fuselage. Examination of the failed surfaces revealed that the left wing separated from the aircraft in a predominately upward direction. The main spar was the first to separate in an upward direction. The rear spar then separated in an upward direction with a slight movement towards the rear. The probable cause of the separation was the choice of basswood for the spars instead of the specified spruce. According to the designer, aircraft grade spruce is the only wood specified for the spars. Builder records indicated the use of basswood for spar construction. Examination confirmed the wood spars were basswood. Basswood is considerably weaker and less stiff than spruce. The FAA Advisory Circular 43.13-1B/2A, Chapter 1, Wood Structures, Table 1-1. Selection and Properties of Aircraft Wood, indicates that spruce is excellent for all uses and is considered as the standard by the FAA. Table 1-1 does not list basswood as a selection of aircraft wood. Chapter 1 Paragraph 1-41 states in part: The type of wood used is critical to the structural strength of the aircraft.
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, private
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 4,500 hours in all
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rear
The aircraft
- Airframe total time: 115 hours
- Last inspection: annual inspection, June 30, 1999; 22 hours since
- Maximum gross weight: 1,300 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-235-C1 (piston); 0 hours total
The flight
- Departed from: CXO at 10:12 pm
- Flight plan: none
- Runway 14, 6,000 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 140° at 11 knots, gusting 18
- Visibility: 10 statute miles
- Sky: broken clouds at 5,000 ft; not recorded
- Temperature: 84°F (29°C), dew point 64°F (18°C)
- Altimeter: 29.00 inHg
- Observation at 11:07 pm from CXO
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.