SEA07CA185 · Hammer Thorp T-18
Hammer Thorp T-18 · Accident: forced landing
From Seattle Paine Field International Airport (PAE) to Seattle Paine Field International Airport (PAE)
Event
- NTSB case
- SEA07CA185
- 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
- Unknown
- 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
Hammer Thorp T-18
- Aircraft type
- Hammer THORP T-18
- 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
- N3715
- Operator
- Robert Hammer
- Onboard fatalities
- Unknown
- Route
- From Seattle Paine Field International Airport (PAE), Everett, WATo Seattle Paine Field International Airport (PAE), Everett, WA
- 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
- Landing · emergency landing
- 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
- Forced landing
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Pilot in command › Airspeed, excessive
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot reported that the takeoff on runway 34L seemed normal until he raised the flaps. The pilot then heard a "big bang [that] shook the entire airplane" and he noticed that the canopy had come unlatched. Concerned that the canopy could possibly depart the aircraft and damage the tail, the pilot declared an emergency and circled left to land on runway 11. The pilot aligned the aircraft with the runway, but the airplane's airspeed was excessive for a normal touchdown point. When the pilot realized that he was "too fast", he pulled the throttle to idle and pulled the mixture out to stop the engine. The aircraft did not touchdown until it reached the numbers at the departure end of the runway. During the landing roll, the aircraft rolled across taxiway Golf, runway 16L-34R, and taxiway Foxtrot. The aircraft continued to roll off the taxiway surface, through the airport perimeter fence and onto a public street, where it encountered uneven terrain and nosed over, coming to rest upside down.
Probable cause
Excessive airspeed during a return for landing which resulted in an overrun. An unlatched canopy, a proper touchdown point not attained and rough terrain were factors.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA07CA185
- Event ID
- 20070723X00995
- Case number
- SEA07CA185
- 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, coordinates. 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: 8c3d4a29b12b7be49dc8c7efb26bc80b23d56b1994dbb3603e04c7c9db9efd68; retrieved 2026-09-21T18:28:29.702Z.