# AD 75-20-06: Vertical Tubes

- Type: Airworthiness directive
- Status: Historical
- Products: Alexandria 14-19-3A, 17-30, 17-31, 17-31TC, 17-30A, 17-31A and 17-31ATC
- Effective: September 26, 1975
- Superseded by: [AD 2014-20-12](https://openairdocs.org/ad/2014-20-12)
- Product type: Aircraft, Small airplane
- Amendment: 39-2372
- Registered aircraft: 634 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9E57BE9F4F965E8E86256A34005821C3.0001
- DRS record last changed: August 7, 2025
- Page: https://openairdocs.org/ad/75-20-06

## The airworthiness directive

75-20-06 BELLANCA: Amendment 39-2372. Applies to Model 17-30, 17-30A (S/N 30263 through S/N 76-30811), 17-31, 17-31TC, 17-31ATC (S/N 30004, S/N 31004 through S/N 76-31124), 14-19-3A, and 17-31A (S/N 32-15 through S/N 76-32-163) airplanes certificated in all categories.

Compliance required upon accumulation of 300 hours time in service or within the next 25 hours time in service from the effective date of this Airworthiness Directive (whichever occurs later) unless already accomplished, and thereafter at intervals not to exceed 100 hours time in service from the last inspection until Bellanca Kit SK1234789-0004 is accomplished.

To detect cracks in either vertical side fuselage tube (F. S. 7), which is adjacent to the horizontal stabilizer carry-through, in the area near the upper fuselage longeron, accomplish the following:

A. Inspect the vertical tube for circumferential cracks at the upper weld, and between the upper weld and the horizontal stabilizer carry-throughtube, all around the tube.

B. If cracks are found, repair and modify in accordance with Bellanca Kit SK1234789-0004 or an equivalent approved by the Chief, Engineering and Manufacturing Branch, Great Lakes Region, before further flight, except that the airplane may be flown, in accordance with FAR 21.197, to a base where the repair can be performed.

C. If no cracks are found, no further action is required until the next inspection.

Bellanca Service Letter No. 85 or 85A pertains to this same subject.

This amendment becomes effective September 26, 1975.

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A3](https://openairdocs.org/tcds/1A3): Bellanca Aircraft Inc.; names 4 of 7 models: 17-31TC, 17-30, 14-19-3A, 17-31
- [TCDS A18CE](https://openairdocs.org/tcds/A18CE): Bellanca Aircraft Inc.; names 3 of 3 models: 17-31ATC, 17-31A, 17-30A

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 634 (634 by airframe model, 0 by engine model)
- Makers: Bellanca 631, Downer 2, Alexandria 1

Models with the most aircraft:

- [Bellanca 17-30A](https://openairdocs.org/model/bellanca-17-30a): 399 aircraft (airframe model)
- [Bellanca 17-30](https://openairdocs.org/model/bellanca-17-30): 83 aircraft (airframe model)
- [Bellanca 17-31ATC](https://openairdocs.org/model/bellanca-17-31atc): 71 aircraft (airframe model)
- [Bellanca 17-31A](https://openairdocs.org/model/bellanca-17-31a): 71 aircraft (airframe model)
- [Bellanca 17-31](https://openairdocs.org/model/bellanca-17-31): 5 aircraft (airframe model)
- [Bellanca 14-19-3A](https://openairdocs.org/model/bellanca-14-19-3a): 2 aircraft (airframe model)
- [Downer 14-19-3A](https://openairdocs.org/model/downer-14-19-3a): 2 aircraft (airframe model)
- [Alexandria 17-30A](https://openairdocs.org/model/alexandria-17-30a): 1 aircraft (airframe model)

All 9 models: https://openairdocs.org/ad/75-20-06/models.md
Every aircraft: https://openairdocs.org/ad/75-20-06/aircraft.md

## Related documents

- [AD 2014-20-12](https://openairdocs.org/ad/2014-20-12): Fuselage · Alexandria 14-19-3A, 17-30, 17-30A and 4 more. Effective Nov 12, 2014. Supersedes this AD

Its text cites no advisory circulars or STCs.

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