DEN07IA066 · Diamond Aircraft Industries DA-20-C1
Diamond Aircraft Industries DA-20-C1 · Incident: airframe, component or system failure while maneuvering
From Pueblo Memorial Airport (KPUB) to Pueblo Memorial Airport (KPUB)
Event
- NTSB case
- DEN07IA066
- 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
- Incident
- 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
Diamond Aircraft Industries DA-20-C1
- Aircraft type
- Diamond DA-20
- 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
- N921DA
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Pueblo Memorial Airport (KPUB), Pueblo, COTo Pueblo Memorial Airport (KPUB), Pueblo, CO
- 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
- Maneuvering
- 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
- None
Cause areas
- Manufacturer › Maintenance, installation, inaccurate
- Miscellaneous, bolt/nut/fastener/clamp/spring › Failure, total
- Miscellaneous, bolt/nut/fastener/clamp/spring › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The flight instructor reported that abnormal nose-up trim was required while in flight. The flight concluded without additional or further incidence. After the training flight a 2 to 3-inch gap between the horizontal and vertical stabilizer was noted. Examination of the airplane revealed two bolts, securing the front horizontal stabilizer mounting bracket to the vertical stabilizer, had failed. Examination of the bolts revealed failure due to undetected fatigue. On the failed bolts, the sizes of the final overstress regions were very small indicating that peak and mean loads on the bolts were also small. This would indicate that only a small or marginal preload was present on the bolts. Insufficient preload could be the result of low installation torque or the loss of preload during service. The off center wear on the washers suggests that the fastened surfaces may not have been in alignment allowing the installation preload to quickly degrade.
Probable cause
The failure of the horizontal stabilizer forward bracket bolts due to insufficent preload during factory installation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN07IA066
- Event ID
- 20070313X00280
- Case number
- DEN07IA066
- 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, damage. 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: 4229b224190aad2d61748aba758196fbd274b1f7cac67c786323abcd865116a0; retrieved 2026-09-22T04:00:29.197Z.