# Tab structure (on elevator)

- Type: NTSB finding subsection
- Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › [Aircraft structures](https://openairdocs.org/ntsb-findings/0103) › [Empennage structure](https://openairdocs.org/ntsb-findings/010355) › Tab structure (on elevator)
- NTSB code: 01035523
- Cases: 4
- In the probable cause: 4
- Fatal cases: 1
- All cases: https://openairdocs.org/ntsb-findings/01035523/cases.md
- Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/01035523/cases.md?cause=1
- Page: https://openairdocs.org/ntsb-findings/01035523

## Cases per year (in the probable cause / all)

- 2011: 1 / 1
- 2012: 1 / 1
- 2014: 1 / 1
- 2015: 1 / 1

## Defining events in these cases

- [Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333): 3 cases
- [Aircraft structural failure](https://openairdocs.org/ntsb-events/337): 1 cases

## Aircraft models (registry)

- [Dehavilland DHC-3](https://openairdocs.org/model/dehavilland-dhc-3): 2 cases
- [North American/Aero Classics P-51D](https://openairdocs.org/model/north-american-aero-classics-p-51d): 1 cases
- [Frederick F 1](https://openairdocs.org/model/frederick-f-1): 1 cases

## Other findings in the same cases

- [Fabrication](https://openairdocs.org/ntsb-findings/02062025) (Personnel issues): 2 cases
- [Scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010) (Personnel issues): 2 cases
- [Documentation/record keeping, general](https://openairdocs.org/ntsb-findings/04033000) (Organizational issues): 1 cases
- [Airport facilities/design, general](https://openairdocs.org/ntsb-findings/03017000) (Environmental issues): 1 cases
- [Use of equip/system](https://openairdocs.org/ntsb-findings/02063015) (Personnel issues): 1 cases
- [Action, general](https://openairdocs.org/ntsb-findings/02041000) (Personnel issues): 1 cases
- [Airspeed](https://openairdocs.org/ntsb-findings/01062010) (Aircraft): 1 cases
- [Performance/control parameters, general](https://openairdocs.org/ntsb-findings/01062000) (Aircraft): 1 cases
- [Elevator/tab attach fitting](https://openairdocs.org/ntsb-findings/01035552) (Aircraft): 1 cases
- [Elevator misc structure](https://openairdocs.org/ntsb-findings/01035524) (Aircraft): 1 cases

## Newest cases

- [NTSB ANC15LA037](https://openairdocs.org/ntsb/ANC15LA037), Jun 4, 2015: Dehavilland DHC-3T (N3125N), Skwentna, AK, substantial damage. Probable cause: The flutter failure of the right elevator servo tab due to the improper fabrication of the servo tab and maintenance personnel’s subsequent failure to detect anomalies with the servo tab.
- [NTSB ANC14LA035](https://openairdocs.org/ntsb/ANC14LA035), May 30, 2014: Dehavilland DHC-3T (N3125N), Homer, AK, substantial damage. Probable cause: The flutter failure of the right elevator servo tab due to the improper fabrication of the servo tab and maintenance personnel’s subsequent failure to detect anomalies with the servo tab.
- [NTSB WPR12FA421](https://openairdocs.org/ntsb/WPR12FA421), Sep 14, 2012: Frederick F 1 (N158CF), Reno, NV, substantial damage. Probable cause: The pilot’s operation of the airplane above the established never-exceed speed and the incorrect installation of the trim tab control horn, which resulted in the flutter of the left elevator trim tab.
- [NTSB WPR11MA454](https://openairdocs.org/ntsb/WPR11MA454), Sep 16, 2011: North American/Aero Classics P-51D (N79111), Reno, NV, substantial damage, 11 fatal. Probable cause: The reduced stiffness of the elevator trim tab system that allowed aerodynamic flutter to occur at racing speeds. The reduced stiffness was a result of deteriorated locknut inserts that allowed the…

NTSB has coded findings and defining events since 2008; earlier cases used its older occurrence and cause codes and aren't counted.

Findings: https://openairdocs.org/ntsb-findings.md. Defining events: https://openairdocs.org/ntsb-events.md. Phases of flight: https://openairdocs.org/ntsb-phases.md. Every investigation, filtered by finding, event, phase, state, year or model: https://openairdocs.org/ntsb.md (for example ?state=MI&fatal=1).

NTSB's definitions: Accident and incident, 49 CFR 830.2 (https://www.ecfr.gov/current/title-49/subtitle-B/chapter-VIII/part-830/subpart-A/section-830.2), CICTT occurrence categories (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/OccurrenceCategoryDefinitions.pdf), CICTT phases of flight (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/PhaseofFlightDefinitions.pdf), and NTSB coding manual, before 2008 (PDF) (https://www.ntsb.gov/GILS/Documents/codman.pdf). NTSB publishes no definitions for its findings, only their names.

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