CHI96LA041 · McClung SEA HAWK
McClung SEA HAWK · Accident: airframe, component or system failure en route
From Poplar Grove Airport (C77) to an unrecorded destination
Event
- NTSB case
- CHI96LA041
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
McClung SEA HAWK
- Aircraft type
- Mcclung SEA HAWK
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N391SP
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Poplar Grove Airport (C77), Belvidere, ILTo not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Owner/builder › Aircraft/equipment inadequate
- Wing › Debonded
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that approximately 10 minutes into the flight a 'thump' was heard from the right rear of the airplane. He stated that besides a slight list to the right, he did not notice anything unusual with the airplane's flying characteristics. He decided to make a precautionary landing after noticing a rapid depletion of indicated fuel quantity on the upper wing tank gauge. After landing, the pilot and passenger exited the airplane and realized the airplane's upper right wing had departed the airplane. A fire started and consumed the entire airplane. The wing was found 7/8 mile from the resting point of the airplane. Examination of the failed upper right wing, revealed the wing had failed due to compression failure. The investigation also revealed that the failure was due to the presence of unbonded areas between the spar cap and the bidirectional fiberglass that secures the web to the cap. It is not possible to inspect these areas because they are not accessible after construction.
Probable cause
the failure of the upper right wing due to the presence of unbonded areas between the spar cap and the bidirectional fiberglass. The unbonded areas were due to the inadequate manufacturing of the airplane by the owner/builder. A factor in the accident was the inadequate design by the kit manufacturer.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI96LA041
- Event ID
- 20001207X04835
- Case number
- CHI96LA041
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: da4e495612e5c4aded843401618a727fbc7be88e252222392a02320f01c99845; retrieved 2026-09-22T23:01:06.497Z.