Type Record · As of May 3, 2026
WACO DSO
Fixed Wing Single Engine · HISPANO E
Registered
7
Year Range
1929–1929
NTSB Events
2
Airworthiness Directives
0
01 / Distribution
Where the fleet lives and was built
Counts of currently-registered WACO DSO aircraft by US state and decade of manufacture, sourced from the FAA Aircraft Registry.
By State (top 10)
- CA 28.6% 2
- MT 14.3% 1
- MN 14.3% 1
- OH 14.3% 1
- FL 14.3% 1
- OR 14.3% 1
By Decade of Manufacture
- 1920s 42.9% 3
- Unknown 57.1% 4
02 / NTSB Records
Events involving WACO DSO aircraft
2 event(s) on file. Showing the most recent 2.
-
Sep 6, 1971
N8538XSALMON, Idaho
NTSB Docket → -
Jun 26, 1964
N8538XANAPRA, New Mexico Minor
NTSB Docket →
02c / Academic Research
Scholarly work mentioning WACO DSO
Papers and reports across NASA, NTSB, FAA CAMI, AOPA ASI, Embry-Riddle, arXiv, and the broader academic graph that mention this airframe. Title or keyword match — drill into each for full abstract + author list + PDF link.
- NASA NTRS 2019 · Conference Paper
Analyzing a Mid-Air Collision Over the Hudson River
On August 8, 2009, a private airplane collided with a sightseeing helicopter over the Hudson River near Hoboken, New Jersey.
- arXiv 2012 · arXiv preprint
The Critical Richardson Number and Limits of Applicability of Local Similarity Theory in the Stable Boundary Layer
Measurements of atmospheric turbulence made over the Arctic pack ice during the Surface Heat Budget of the Arctic Ocean experiment (SHEBA) are used to determine the limits of applicability of Monin-Ob…
- arXiv 2025 · arXiv preprint
Numerical investigation of engine position effects on contrail formation and evolution in the near-field of a realistic aircraft configuration
The present study investigates the impact of engine position on contrail formation and near-field evolution in a realistic three-dimensional aircraft configuration.
- arXiv 2022 · arXiv preprint
Ice friction at the nanoscale
The origin of ice slipperiness has been a matter of great controversy for more than a century, but an atomistic understanding of ice friction is still lacking.
- arXiv 2021 · arXiv preprint
Axisymmetric simulations of the convective overstability in protoplanetary discs
Protoplanetary discs at certain radii exhibit adverse radial entropy gradients that can drive oscillatory convection (`convective overstability'; COS).
- arXiv 2021 · arXiv preprint
Lifshitz theory of wetting films at three phase coexistence: The case of ice nucleation on Silver Iodide (AgI)
Hypothesis: As a fluid approaches three phase coexistence, adsorption may take place by the successive formation of two intervening wetting films.
Browse the full corpus — academia portal ↗
03 / Airworthiness Directives
FAA directives applicable to WACO DSO
No matching airworthiness directives are on file for this make and model in the Federal Register.
04 / Type Certificate Data Sheets
FAA TCDS for WACO DSO
The TCDS is the legal certification document — weight limits, performance, equipment, AD compliance times, operating limitations. 1 match in the FAA catalog.
- ATC 42 Waco Current Rev 0 ·
The Waco Aircraft Company
Models: DSO
06 / Supplemental Type Certificates
Modifications approved for WACO DSO
16 STCs on file — every FAA-approved modification, alteration, or installation for this aircraft. STOL kits, avionics, fuel systems, floats, engine swaps, you name it.
-
12/20/2017
STC SA01406NY
Installation of Airwolf remote mounted engine oil filter kit AFC-K017 on single and multi-engine fixed light aircraft and\nrotary wing
Airwolf Filter Corporation
-
10/31/2012
STC SA01406NY
Installation of Airwolf remote mounted engine oil filter kit AFC-K017 on single and multi-engine fixed light aircraft and\nrotary wing
Airwolf Filter Corporation
-
12/09/2009
STC SA2693NM (PAGE 2)
Installation of Electronics International digital volt/amp gauges and accessories.
Electronics International Inc.
-
07/24/2008
STC SA02033AT (PAGE 5)
Modification to install an air-oil separator to prevent oil from being aspirated from the engine breather line (47J series w stc's SH4-235SW, SH4-826SW or SH479SW)
M-20 Oil Separators LLC
-
03/29/2006
STC SA02268CH (PAGE 5)
Installation of Airwolf Filter Corp. Air Oil Separator
Airwolf Filter Corporation
-
01/24/2005
STC SA2693NM
Installation of Electronics International digital volt/amp gauges and accessories.
Electronics International Inc.
-
10/24/2000
STC SA2687NM (PAGE 2)
Installation of Truboplus/ Electronics Int'l gauges and switches.
Aero Manufacturing Inc.
-
07/25/1997
STC SA01438AT
Restores aircraft from restricted category to normal category by removing agricultural spray equipment and adds propeller models as listed in FAA approved Supplemental Flight Manua…
Stilley John D
-
03/09/1993
STC SA1626NM Page 2
Installation of Electronics Int'l Digital EGT/CHT Instruments and accessories. (201 Series)
Electronics International
-
02/24/1992
STC SA2687NM
Installation of Truboplus/ Electronics Int'l gauges and switches.
ACD Corporation
-
06/06/1990
STC SA2350NM Page 2
Installation of Electronics International Inc digital carburetor/outside air temperature gauges
Electronics International
-
10/12/1989
STC SA4302NM (PAGE 3)
Installation of Electronics Int'l digital automatic engine analyzer.
Electronics International
-
01/26/1988
STC SA2693NM
Installation of Electronics International digital volt/amp gauges and accessories.
Electronics International
-
05/26/1987
STC SA2350NM (PAGE 2)
Installation of Electronics International Inc Digital carburetor/outside air temperature gauges listed on the attached continutation sheet and the associated accessories
Electronics International
-
02/06/1986
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
-
02/16/1984
STC SA2190NM Page 2
Installation of electronics International Digital Volt/Amp Gauges and Accessories.
Electronics International
04 / Regulations watching this type
Advisory Circulars and Federal Register activity for WACO DSO
Advisory Circulars
No ACs explicitly mention this type. Showing universal operating-rule ACs that apply to all aircraft.
Recent Federal Register activity
Latest rulemakings touching general operating rules (Part 91) and maintenance rules (Part 43).
- 2026-04-17 Settlement Policy for Small Unmanned Aircraft System (UAS) Cases FR ↗
- 2026-02-10 Normalizing Unmanned Aircraft Systems Beyond Visual Line of Sight Operations; Reopening of Comment Period; Denial of Extension FR ↗
- 2026-02-02 25-Hour Cockpit Voice Recorder (CVR) Requirement, New Aircraft Production FR ↗
- 2026-01-28 Normalizing Unmanned Aircraft Systems Beyond Visual Line of Sight Operations; Reopening of Comment Period FR ↗
- 2026-01-07 Requirements for Interference-Tolerant Radio Altimeter Systems FR ↗
05 / Aircraft of this type
All 7 registered N-numbers
Every tail currently on the FAA registry for this make/model. Click an N-number to query the FAA Aircraft Inquiry; rows flagged ● have NTSB events on file. Tails seeded with full TallyAero pages link directly.
| N-number | St | Year | NTSB | FAA |
|---|---|---|---|---|
| N204M | CA | — | · | Look up ↗ |
| N605N | CA | 1929 | · | Look up ↗ |
| N629N | MT | — | · | Look up ↗ |
| N762K | MN | 1929 | · | Look up ↗ |
| N8538X | OH | — | ● | Look up ↗ |
| N8558 | FL | 1929 | · | Look up ↗ |
| N8599 | OR | — | · | Look up ↗ |
Source — FAA Aircraft Registry · click "Look up" to query the live registry record (owner, address, last airworthiness)
05 / Sources & Methodology
Every count traces back to a primary US-government source
- FAA Aircraft Registry →
Refreshed Apr 27, 2026
Available
- NTSB CAROL →
Refreshed Apr 27, 2026
Available
- Federal Register (FAA Airworthiness Directives) →
Refreshed Apr 27, 2026
Available
We render counts and lists as the agency publishes them. Read the methodology →