# N704K: Waco BSO

- Status: Valid registration
- Airframe: [Waco BSO](https://openairdocs.org/model/waco-bso) (registry code 9601204, 3 seats)
- Data sheets: [TCDS ATC 168](https://openairdocs.org/tcds/ATC%20168) (The Waco Aircraft Company) (OpenAirDocs)
- Serial number: A-164
- Type: Fixed wing single engine
- Engine type: Reciprocating
- Certificate issued: March 25, 2009
- Expires: February 28, 2030
- Mode S code: A9644B
- Registered owner: [Hirtle Alan L](https://openairdocs.org/faa-owner/HIRTLE%20ALAN%20L)
- Location: [Oro Valley, AZ](https://openairdocs.org/faa-place/AZ/Oro%20Valley)
- Owner type: Individual
- Owner's area on the map: 32.4684° N, 110.9815° W: Placed by OpenAirDocs at the center of ZIP code 85755, within about 3 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=704K
- Page: https://openairdocs.org/aircraft/N704K

From the FAA registry file of October 24, 2026. ADs below are matched by the registry's airframe and engine model codes. They may apply; each AD's applicability can narrow it by serial number, part number or installed equipment. This is not a compliance determination.

## ADs that may apply (OpenAirDocs): 0 in force

### Matched by airframe (Waco BSO)

None in force.

## Information bulletins (advisory)

None matched.

## NTSB investigations

None matched to N704K.

## FAA accident and incident reports

None matched to N704K.

## Service difficulty reports

None filed for this aircraft. Matched to this aircraft by N-number and event date, checked against the reported serial number, make and model.

## STCs that may be installed (OpenAirDocs) (11)

Approved for this aircraft's airframe or engine model, in force first, then newest. The registry doesn't record which STCs an aircraft has; its records do.

### Approved for the airframe (Waco BSO)

- [STC SA04652CH](https://openairdocs.org/stc/SA04652CH): To allow use of 100R grade aviation fuel meeting Swift Fuel, LLC specification. Swift Fuels LLC
- [STC SA01406NY](https://openairdocs.org/stc/SA01406NY): Installation of Airwolf remote mounted engine oil filter kit AFC-K017 on single and multi-engine fixed light aircraft and rotary wing. Airwolf Filter Corporation
- [STC SA2693NM](https://openairdocs.org/stc/SA2693NM): Installation of Electronics International digital volt/amp gauges and accessories. Electronics International Inc
- [STC SA02033AT](https://openairdocs.org/stc/SA02033AT): Modification to install an air-oil separator to prevent oil from being aspirated from the engine breather line. M-20 Oil Separators LLC
- [STC SA2687NM](https://openairdocs.org/stc/SA2687NM): Installation of Truboplus/ Electronics Int'l gauges and switches. Aero Manufacturing Inc
- [STC SA1626NM PAGE 2](https://openairdocs.org/stc/SA1626NM%20PAGE%202): Installation of Electronics Int'l Digital EGT/CHT Instruments and accessories. (201 Series). Electronics International
- [STC SA2350NM PAGE 2](https://openairdocs.org/stc/SA2350NM%20PAGE%202): Installation of Electronics International Inc digital carburetor/outside air temperature gauges. Electronics International
- [STC SA4302NM](https://openairdocs.org/stc/SA4302NM): Installation of Electronics Int'l digital automatic engine analyzer. Electronics International
- [STC SA3862NM PAGE 2](https://openairdocs.org/stc/SA3862NM%20PAGE%202): Installation of Electronics International Primary TIT/EGT/CHT instruments, remote switches and associated accessories. Electronics International
- [STC SA2190NM PAGE 2](https://openairdocs.org/stc/SA2190NM%20PAGE%202): Installation of electronics International Digital Volt/Amp Gauges and Accessories. Electronics International
- [STC SA2350NM](https://openairdocs.org/stc/SA2350NM) (historical): Installation of Electronics International Inc digital carburetor/outside air temperature gauges listed on the attached continuation sheet and the associated accessories. Electronics International

## Earlier aircraft with N704K

The FAA can reassign an N-number once a registration is cancelled. These aircraft carried N704K before.

- [Cancelled 1948-04-29](https://openairdocs.org/deregistered/N704K-1948-04-29): Great Lakes 2T-1A, S/N 51. Owner: [New Mexico State Board Of Vocational Education](https://openairdocs.org/faa-owner/NEW%20MEXICO%20STATE%20BOARD%20OF%20VOCATIONAL%20EDUCATION), [Santa Fe, NM](https://openairdocs.org/faa-place/NM/Santa%20Fe)

## Related

- Other Waco BSO aircraft: https://openairdocs.org/model/waco-bso/aircraft.md

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