How to Read a Type Certificate Data Sheet (TCDS) for the A&P Oral

October 27, 2026 · Primary sources checked October 27, 2026

A type certificate data sheet (TCDS) describes a certificated aircraft, engine, or propeller and its certification conditions and limitations. For the Airframe and Powerplant (A&P) oral, our advice is to explain which model and limitation you are reading rather than recite a number without its conditions. The Airman Certification Standards (ACS) for the A&P oral and practical (O&P) test list knowledge of TCDSs (AM.I.I.K9) and locating TCDS information (AM.I.I.S6) as separate elements.

FAA-H-8083-30B, Aviation Maintenance Technician Handbook–General (2023), printed 2-30, PDF 79, Type Certificate Data Sheets (TCDS) · FAA-S-ACS-1, Aviation Mechanic General, Airframe, and Powerplant Airman Certification Standards, printed 14, PDF 19, AM.I.I.K9 · FAA-S-ACS-1, Aviation Mechanic General, Airframe, and Powerplant Airman Certification Standards, printed 15, PDF 20, AM.I.I.S6

On this page

What belongs in a TCDS?
Open one real sheet: 3A12, Revision 89
How does an STC change the reference trail?
Finding an item during O&P preparation
Before the oral

What belongs in a TCDS?

The Federal Aviation Administration (FAA) describes TCDSs as formal descriptions that list type-certification limitations and information. Examples in the Aviation Maintenance Technician Handbook–General include engine make and model, fuel type, engine limits, airspeed limits, maximum weight, and minimum crew. The handbook says TCDSs are part of the type certificate (TC), and a TCDS is evidence the product has been type certificated.

FAA-H-8083-30B, Aviation Maintenance Technician Handbook–General (2023), printed 2-30, PDF 79, Type Certificate Data Sheets (TCDS) · FAA-H-8083-30B, Aviation Maintenance Technician Handbook–General (2023), printed 2-30, PDF 79, Type Certificate Data Sheets (TCDS), examples

Aircraft specifications and TCDSs both state essential factors and conditions for U.S. airworthiness certification. The handbook says specifications are no longer issued but remain in effect and will be further amended. A specification is not part of a TC, and a specification covering a type-certificated product may be converted to a TCDS at the TC holder’s option, with an equipment list.

Open one real sheet: 3A12, Revision 89

The worked example is FAA TCDS No. 3A12, Revision 89, dated September 15, 2026, for Textron Aviation’s listed 172 models. The FAA’s Dynamic Regulatory System (DRS) identified that revision as Current when checked on October 27, 2026. Section I is Model 172; later models appear in later sections, and some sections cover more than one model. The numbers below belong to Section I, not automatically to a 172N or 172S.

FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Cover / number, revision, date · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Section I, Model 172 · FAA DRS: 3A12, Current, Revision 89, September 15, 2026, DRS Details: Status, Revision Number, Revision Date

Section I identifies the engine as Continental O-300-A or O-300-B. The “Serial Numbers Eligible” line on printed page 2 lists 610, 612, 615, 28000 thru 29999, 36000 thru 36999, and 46001 thru 46754. Our advice: read the model line and the serial-number line before quoting any limit from that section.

FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Section I, Engine · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 2, PDF 2, Section I, Serial Numbers Eligible

Item to locate	What Section I prints	Where to point
Fuel	“80/87 minimum grade aviation gasoline”	Printed 1 / PDF 1, *Fuel
Normal-category center of gravity (CG)	“(+40.8) to (+46.4) at 2200 lb.”; “(+36.4) to (+46.4) at 1733 lb.”	Printed 2 / PDF 2, C.G. Range
Utility-category CG	“(+38.4) to (+40.3) at 1950 lb.”; “(+36.4) to (+40.3) at 1733 lb. or less”	Printed 2 / PDF 2, C.G. Range
Between the CG points	“Straight line variation between points given.”	Printed 2 / PDF 2, C.G. Range
Aileron travel	Up 20°; Down 14°	Printed 2 / PDF 2, Control Surface Movements

FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Section I, *Fuel · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 2, PDF 2, Section I, C.G. Range, Normal · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 2, PDF 2, Section I, C.G. Range, Utility · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 2, PDF 2, Section I, C.G. Range · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 2, PDF 2, Section I, Control Surface Movements

The first page carries a warning: use of alcohol-based fuels can cause serious performance degradation and fuel system component damage and is therefore prohibited on Cessna airplanes. Our advice: keep that prohibition attached to the fuel example. The printed grade is a reading exercise for this sheet, not an authorization to fuel any aircraft from a blog table.

FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, WARNING

How does an STC change the reference trail?

A supplemental type certificate (STC) approves a modification to a product. The handbook says the STC defines the product design change and states how the modification affects the existing type design; the FAA’s STC page says an STC approves not only the modification but also how that modification affects the original design. Our advice: when a modification is installed, check the applicable STC and its supporting data alongside the basic sheet.

FAA-H-8083-30B, Aviation Maintenance Technician Handbook–General (2023), printed 2-27, PDF 76, Supplemental Type Certificates (STC) · FAA, Supplemental Type Certificates, Opening definition

Possessing an STC document does not itself confer the right to use the design data or install the modification. Section 91.403(d) prohibits an alteration based on an STC unless the owner or operator holds that STC or has written permission from its holder.

FAA-H-8083-30B, Aviation Maintenance Technician Handbook–General (2023), printed 2-30, PDF 79, STC use rights · 14 CFR §91.403(d)

Finding an item during O&P preparation

Our advice: use a repeatable search order—TC number and revision, exact model, serial applicability, item heading, then related notes and approved changes. When practicing with a sheet, say the heading and the condition together: “Normal category, at 2200 lb., on printed page 2.” A correct limit detached from its category or weight is an incomplete explanation.

The FAA Design Approvals page links to the DRS TCDS collection. Our advice: use that route to check the document and its current revision before study or actual work. ACS element AM.I.I.S6 reads: “Locate applicable FAA aircraft specifications and FAA TCDS for an aircraft or component.”

FAA, Design Approvals: TCDS collection, Design Approval Resources · FAA-S-ACS-1, Aviation Mechanic General, Airframe, and Powerplant Airman Certification Standards, printed 15, PDF 20, AM.I.I.S6

The ACS says that during the oral portion of the test, the applicant is not allowed to use any reference material to answer the oral questions asked by the examiner. Our advice: practice navigating the TCDS while studying, then close it and explain what information the sheet supplies. Practical reference permission is a separate matter, covered in our guide to reference rules on the oral and practical.

FAA-S-ACS-1, Aviation Mechanic General, Airframe, and Powerplant Airman Certification Standards, printed A-1, PDF 65, Appendix 1 / Applicant Responsibilities

Frequently asked questions

Is the TCDS the same thing as an STC?

No, the TCDS describes the certificated product and its limitations, while an STC approves a design modification and its effect on the original design. For a modified aircraft, our advice is to check both the TCDS and the applicable STC.

FAA-H-8083-30B, Aviation Maintenance Technician Handbook–General (2023), printed 2-30, PDF 79, Type Certificate Data Sheets (TCDS) · FAA, Supplemental Type Certificates, Opening definition

Can I use the Section I fuel line for every Cessna 172 model?

No, first establish the exact model and applicable section. The example’s original Model 172 has its own engine, fuel, and serial-number entries; a shared TC number does not erase those distinctions.

FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Section I, Model 172 · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Section I, Engine · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 1, PDF 1, Section I, *Fuel · FAA TCDS 3A12, Revision 89, September 15, 2026, printed 2, PDF 2, Section I, Serial Numbers Eligible

May I keep the sheet open to answer TCDS questions during the O&P oral?

No, the standalone oral’s reference restriction still applies to document questions. Our advice: rehearse the document’s purpose from memory after using the sheet to verify your study answer.

FAA-S-ACS-1, Aviation Mechanic General, Airframe, and Powerplant Airman Certification Standards, printed A-1, PDF 65, Appendix 1 / Applicant Responsibilities

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Related guides

Primary sources

Practice explaining the answer aloud

DMEReady offers an artificial intelligence (AI) voice examiner for oral rehearsal in your phone or computer browser. Speak your answer and respond to follow-up questions. The first drill is free with no sign-up. DMEReady is independent, is not affiliated with or endorsed by the FAA, and uses an AI examiner rather than a human Designated Mechanic Examiner (DME); the rehearsal does not train hands-on practical skills.

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Before the oral

Our advice: explain a document’s purpose, find the model entry, and then answer without the sheet open. The FAA’s Mechanic Test Generator (MTG) FAQ specifies one additional oral question for each missed ACS code, plus at least four randomly generated questions in each section—General, Airframe, and Powerplant. Use the ACS codes on your Airman Knowledge Test Report (AKTR) to target your review, then broaden it beyond this one topic.

FAA Mechanic Test Generator FAQs, updated May 22, 2023, PDF 3 (no printed page number), Oral-related Questions / How is the oral portion of the test changing? · FAA Mechanic Test Generator FAQs, updated May 22, 2023, PDF 4 (no printed page number), Oral-related Questions

Explain the limit out loud, then check its source.

About this guide: drafted with AI from the FAA sources listed on this page and checked claim by claim against them. Not reviewed by an A&P mechanic or DME. How we make our guides

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