# N6940: 1929 Waco ASO - Status: Valid registration - Airframe: [Waco ASO](https://openairdocs.org/model/waco-aso) (registry code 9601202, 3 seats) - Engine: [Continental W670 series](https://openairdocs.org/engine/continental-w670-series) (registry code 17018) - Data sheets: [TCDS ATC 41](https://openairdocs.org/tcds/ATC%2041) (The Waco Aircraft Company) (OpenAirDocs) - Serial number: 3004 - Year built: 1929 - Type: Fixed wing single engine - Engine type: Reciprocating - Airworthiness: Restricted, agriculture and pest control - Airworthiness date: July 10, 1956 - Certificate issued: September 13, 2023 - Expires: September 30, 2030 - Mode S code: A93BEA - Owner type: Individual - FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=6940 - Page: https://openairdocs.org/aircraft/N6940 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. The registry lists only the engine series, so ADs for every Continental W670 model are included. ## ADs that may apply (OpenAirDocs): 2 in force ### Matched by airframe (Waco ASO) None in force. ### Matched by engine (Continental W670 series) - [AD 53-09-04](https://openairdocs.org/ad/53-09-04): Propeller Blades · Continental W-670-9A - [AD 50-12-01](https://openairdocs.org/ad/50-12-01): Propeller Blade · Hamilton Standard Propeller Blades, W670-16, W670-6A and 1 more ## Information bulletins (advisory) None matched. ## NTSB investigations None matched to N6940. ## FAA accident and incident reports None matched to N6940. ## 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) (32) 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 ASO) - [STC SA04652CH](https://openairdocs.org/stc/SA04652CH): To allow use of 100R grade aviation fuel meeting Swift Fuel, LLC specification. Swift Fuels LLC - [STC SA4503NM](https://openairdocs.org/stc/SA4503NM): Remove original cloth covering and install Ceconite covering. Ceconite Division of Poly-Fiber Inc - [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 SA00478CH](https://openairdocs.org/stc/SA00478CH): Installation of Cooper Superflite 102 Fabric. Aviation Products Systems Inc - [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 ### Approved for the engine (Continental W670 series) - [STC SE04651CH](https://openairdocs.org/stc/SE04651CH): To allow use of l00R grade aviation fuel meeting Swift Fuel, LLC specification SPEC-l00R-22. Swift Fuels LLC. Lists W670-16 - [STC SE01966WI](https://openairdocs.org/stc/SE01966WI): Use of GAMI G100UL High Octane Unleaded Avgas in spark ignition piston aircraft engines. General Aviation Modifications Inc. Lists W670-16 - [STC SE8776SW](https://openairdocs.org/stc/SE8776SW): Installation of coated cylinders and piston rings. Continental Motors, Inc - [STC SE7492SW](https://openairdocs.org/stc/SE7492SW): Install Delco starter P/N 1108684 or Eclipse/Bendix Utica model E80 starters. Rare Aircraft Ltd. Lists W670-16 - [STC SE04136AT](https://openairdocs.org/stc/SE04136AT): Installation of Bendix Scintilla WL-7A Battery Ignition Timer (distributor) modified from a breaker points and condenser design to a Hall Effect electronic sensor design. Air Repair Inc. Lists W670-23 - [STC SE00809WI](https://openairdocs.org/stc/SE00809WI): Installation of a modified alternate source of supply, engine ignition coil assembly and condenser. Air Repair Inc. Lists W670-23 - [STC SE01652WI](https://openairdocs.org/stc/SE01652WI): Modification of engine to replace contact points and condenser controlled Bendix Scintilla WL-7A battery timer (distributor) with an electronically controlled WL-7A-M battery timer. Radial Engines Ltd. Lists W670-23 - [STC SE01144SE](https://openairdocs.org/stc/SE01144SE): Installation of Olde Thyme Aviation, Inc. pistons, P/N OTA-4032-T6 or Air Repair, Inc. pistons, P/Ns AR4177 (5 each) and AR4177-1 (2 each), to replace Teledyne Continental Motors pistons P/N 4177. Air Repair Inc. Lists W670-16 - [STC SE01243WI](https://openairdocs.org/stc/SE01243WI): Installation of Barron Aviation intake tube drain kits on the engines listed on the attached FAA Approved Model List (AML) No. SE01243WI, dated April 26, 2004, or later FAA Approved revision. Barron Aviation. Lists W670-16 - [STC SE01145SE](https://openairdocs.org/stc/SE01145SE): Option 1) Installation of Olde Thyme Aviation Inc. crankshaft bearings OTA-21201-AB (rear) and OTA-21301-FB (front) Option 2) Installation of Olde Thyme Aviation Inc. replacement intake valve guides P/N OTA-20241-IG Option 3) Installation of Olde Thyme Aviation Inc. replacement exhaust valve guides P/N OTA-20406-EG. Air Repair Inc. Lists W670-16 - [STC SE01146SE](https://openairdocs.org/stc/SE01146SE): Option 1) Installation of Gold Coast Aviation crankshaft bearings GCA-21201-AB (rear) and GCA-21301-FB (front) Option 2) Installation of Gold Coast Aviation replacement intake valve guides P/N GCA-20241-IG Option 3) Installation of Gold Coast Aviation replacement exhaust valve guides P/N GCA-20406-EG. Gold Coast Aviation Service Inc. Lists W670-16 - [STC SE00946LA](https://openairdocs.org/stc/SE00946LA): Installation of engine crankshaft front and rear bearings. Holloway Engineering Co. Lists W670-6A - [STC SE00372LA](https://openairdocs.org/stc/SE00372LA): Installation of a Jacobs shielded ignition harness on Teledyne Continental Motors engine models. Aero Engines Inc. Lists W670-16 - [STC SE7491SW](https://openairdocs.org/stc/SE7491SW): Install Scintilla VNM-7DFA magnetos on W-670-6A and -6N engines. Air Repair - [STC SE5879SW](https://openairdocs.org/stc/SE5879SW): Use of Phillips X/C II 20W-50 and25W-60 oil (OSS 55875) in all Avco reciprocating aircraft engines from 65 to 450 BHP. Phillips Petroleum Co - [STC SE4127SW](https://openairdocs.org/stc/SE4127SW): Install modified W-670-23 piston, P/N 4180, to replace W-670-6A piston, P/N 4177. Air Repair. Lists W670-6A - [STC SE2028CE](https://openairdocs.org/stc/SE2028CE): Add the following approved fuel: unleaded automotive gasoline, 87 minimum antiknock index, and leaded automotive gasoline, 88 minimum antiknock index(RON+MON)/2. Intermixing with aviation gasoline also approved. Petersen Aviation Inc - [STC SE5WE](https://openairdocs.org/stc/SE5WE): Compression ratio tank pistons. Salinas Engine Works. Lists W670-24 - [STC SE03079AT](https://openairdocs.org/stc/SE03079AT) (historical): Modify the Teledyne Continental W670 Series aircraft engines by replacing the crankshaft front and rear main ball bearings with higher capacity roller bearings. Air Repair Inc. Lists W670-16 ## Earlier aircraft with N6940 The FAA can reassign an N-number once a registration is cancelled. These aircraft carried N6940 before. - [Cancelled 2007-06-18](https://openairdocs.org/deregistered/N6940-2007-06-18): Walker Robert R AVID FLYER, S/N 123. Triennial form not returned. Owner: [Johnson Robert K](https://openairdocs.org/faa-owner/JOHNSON%20ROBERT%20K), [Leavenworth, WA](https://openairdocs.org/faa-place/WA/Leavenworth) - [Cancelled 1985-10-22](https://openairdocs.org/deregistered/N6940-1985-10-22): Snider WICHAWK, S/N 30. Owner: [Kaufman Don B](https://openairdocs.org/faa-owner/KAUFMAN%20DON%20B), [Los Angeles, CA](https://openairdocs.org/faa-place/CA/Los%20Angeles) ## Related - Other Waco ASO aircraft: https://openairdocs.org/model/waco-aso/aircraft.md - The Continental W670 series engine: https://openairdocs.org/engine/continental-w670-series.md --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.