Updated: Dec 8, 2020

Airworthiness Requirements Lesson by wifiCFI

Aircraft Documents

Required Aircraft Documents Include: (ARROW)

External Data Plate (FAR 45.11)

Airworthiness Certificate (FAR 91.203)

Registration Certificate (FAR 91.203)

Radio Station License (Outside US)

Operating Handbook (AFM or POH) (FAR 91.9)

Weight and Balance (Official from POH)

Compass Deviation Card (FAR 23.1547)

External Data Plate (FAR 45.11)

Must be a fireproof plate.

Must be in a place where it is not likely to be destroyed or lost in an aircraft accident.

Must be on the rear most entrance door or fuselage near the tail surface.

Contains the aircraft’s serial number.

Airworthiness Certificate (FAR 91.203)

Must contain the aircraft’s serial number.

Does not expire as long as the aircraft is maintained in an airworthy condition.

Must be in view for all passengers and crew.

Registration Certificate (FAR 91.203)

Identifies the owner of the aircraft.

Typically valid for 3 years.

Radio Station License

Only required on international flights.

Issued by the FCC.

Operating Handbook (AFM or POH) (FAR 91.9)

Must be on the aircraft for any flight operations.

Must be current and FAA approved.

Cannot be missing pages.

Official Weight and Balance

Typically found in the POH.

Must be current.

Weight and Balance sheets may change with changes in equipment.

Make sure you have a copy of the most current weight and balance.

Make sure it does not say “superseded” on it.

Compass Deviation Card

Must be legible.

Must be placed near or on the aircraft’s magnetic compass.

Required Aircraft Inspections Include (AV1ATES)

Annual Inspection (FAR 91.409)

VOR Check* (FAR 91.171)

100 HR Inspection (FAR 91.409)

Altimeter* (FAR 91.411)

Transponder (FAR 91.413)

ELT Functional and Battery Check (FAR 91.207(c)(d))

Static/Encoder* (FAR 91.411)

*Required for IFR operations only

Annual Inspection (FAR 91.409)

Required every 12 calendar months for all aircraft.

Must be signed off by an IA mechanic.

Can replace a 100 HR Inspection.

Cannot be overflown.


If an aircraft had it’s last Annual Inspection February 26, 2017, when is the next Annual Inspection due?


The last day of February 2018

VOR Inspection (FAR 91.171)

Only required for IFR operations.

Can be signed off by a pilot.

The pilot must note:

Their signature

The location of the VOR Check

Amount of error

Date of VOR Check

Due every 30 days for IFR flying

Types of VOR Checks Include:

VOT (VOR Test Facilities)

Ground Checks

Airborne Checks

Dual VOR Checks

100 HR Inspection (FAR 91.409)

Required for all aircraft that are “for hire.”

Cannot be substituted for an Annual Inspection.

Can be signed off by an A&P or IA Mechanic.

May be overflown by up to 10 hours if:

The aircraft is in transit to get the 100 HR Inspection done.

Any time over 100 hrs must be subtracted from the next 100 HR Inspection.


The aircraft’s last 100 HR Inspection was done at 4228.0 Tach Time.

The previous 100 HR Inspection was done at 4124.0 Tach Time.

When is the next 100 HR Inspection due?

At a Tach Time of 4324.0

Altimeter Inspection (FAR 91.411)

Due every 24 calendar months.

Only required for IFR operations.


An aircraft’s last Altimeter Inspection was done February 26, 2017

When is the next inspection due?

By the last day of February 2019.

Transponder Inspection (FAR 91.413)

Due every 24 calendar months.

Required if flying in transponder airspace.

In which airspace are transponders required? (FAR 91.215)

Class A Airspace

Class B Airspace

Mode C Veil Surrounding Class B Airspace

Class C Airspace

Above 10,000’ MSL

Except at and below 2,500’ AGL (see explanation on next slide)

What are the common transponder squawk codes and their associated meanings?

1200 = VFR

7500 = Hijacking

7600 = Lost Comms

7700 = General Emergency

7777 = Military Intercept

ELT Functional and Battery Inspections (FAR 91.207(c)(d))

ELT stands for “Emergency Locator Transmitter.”

Used to locate aircraft in emergency situations.

ELT Functional Inspection

Due every 12 calendar months

How to test the ELT:

Must be tested only during the first 5 minutes after the hour.

Can only repeat 2 loops.

ELT Battery

The battery must be changed according to the battery expiration date on the ELT.

When the transmitter has been in use for more than 1 cumulative hour.

When ELT Battery is at 50% or lower.

Static and Encoder Inspection (FAR 91.411)

Only required for IFR operations.

Due every 24 calendar months.

Airworthiness Directives (AD) (FAR 39)

An Airworthiness Directive (AD) is essentially a recall for an airplane or airplane part.

However, they differ from other vehicle recalls in the following ways:

They are issued by the FAA.

They are paid for by the aircraft owner, not the manufacturer.

They are mandatory.

It is never legal to operate an aircraft without all of the AD’s in compliance.

Pilot’s may obtain a Special Flight Permit in certain situations.

A full listing of aircraft ADs can be found at the link below:

AD Compliance

AD compliance can either be 1 time or recurring.

Form 337

Form 337s are Major Alterations or Repairs made to an aircraft.

Qualifying Alterations or Repairs need to be accompanied with an FAA form.

The description of the work performed is usually noted on the back side of this page.

Required VFR Day Equipment (FAR 91.205b)

Below is the list of equipment required for aircraft to fly VFR during the day (ATOMATOFLAMES)

Airspeed Indicator


Oil Pressure Gauge

Manifold Pressure Gauge (for each altitude engine)


Temperature Gauge (for each liquid cooled engine)

Oil Temperature Gauge (for each air cooled engine)

Fuel Quantity Indicator (for each fuel tank)

Landing Gear Position Indicators (for aircraft with retractable landing gear)

Anti-Collision Light System

Magnetic Compass

Emergency Locator Transmitter (ELT)

Safety Belts

Required VFR Night Equipment (FAR 91.205c)

Below is the list of equipment required for aircraft to fly VFR at night FLAPS)

All Day VFR Equipment plus:

Fuses (spares)

Landing Light (if the aircraft is for hire)

Anti-Collision Light System

Position Indicator Lights

Source of Electricity

Inoperative equipment (FAR 91.213d)

Can a pilot legally fly with inoperative equipment?

The answer is…


Let’s dive in to Advisory Circular (AC) 91-67 to find out.

First we need to understand some terminology and definitions.

They are:

Deactivation = To make a piece of equipment or an instrument unusable to the pilot or flight crew, preventing its operation.

Inoperative = Means that a system or its component has malfunctioned.

Kinds of Operations List = Specifies the kinds of operations in which the aircraft can be operated (VFR day/night, IFR, Icing). The Kinds of operations list also indicates the installed equipment necessary for that particular operation.

Letter of Authorization (LOA) = Issued by the FSDO (Flight Standards District Office) authorizing an aircraft operator to operate under the provisions of an MEL (Minimum Equipment List).

Master Minimum Equipment List (MMEL) = Contains a list of equipment and instruments that may be inoperative on a specific type of aircraft. The MMEL is type specific.

Minimum Equipment List (MEL) = The specific inoperative equipment document for a particular make and model by aircraft serial number and registration. The MEL is tail number specific.

Supplemental Type Certificate (STC) = A major change in type design not great enough to require a new type certificate.

Type Certificate Data Sheet (TCDS) = Documents issued by the FAA that describe the aircraft’s airworthiness requirements for a specific type, make, and model.

So, if you are an operator that has an LOA to operate under an MEL then you follow the provisions laid out in that MEL.

In this situation you would no longer have to follow the rules listed in 91.207 for required equipment.

You would only follow exactly what the MEL said.

If you do not operate under the provisions of an MEL then you will follow the flow chart seen below.

Special Flight Permit (FAR 21.197)

A special flight permit may be issued for an aircraft that may not currently meet applicable airworthiness requirements but is capable of safe flight, for the following purposes: 

Flying the aircraft to a base where repairs, alterations, or maintenance are to be performed, or to a point of storage. 

Delivering or exporting the aircraft. 

Production flight testing new production aircraft. 

Evacuating aircraft from areas of impending danger. 

Conducting customer demonstration flights in new production aircraft that have satisfactorily completed production flight tests. 

A special flight permit may also be issued to authorize the operation of an aircraft at a weight in excess of its maximum certificated takeoff weight for flight beyond the normal range over water, or over land areas where adequate landing facilities or appropriate fuel is not available.

The issuance of a Special Flight Permit goes as follows:

An applicant for a special flight permit must submit a statement in a form and manner prescribed by the Administrator, indicating:

The purpose of the flight. 

The proposed itinerary. 

The crew required to operate the aircraft and its equipment, e.g., pilot, co-pilot, navigator, etc. 

The ways, if any, in which the aircraft does not comply with the applicable airworthiness requirements. 

Any restriction the applicant considers necessary for safe operation of the aircraft. 

Any other information considered necessary by the Administrator for the purpose of prescribing operating limitations. 

The Administrator may make, or require the applicant to make appropriate inspections or tests necessary for safety.

FAA Sources Used for This Lesson

Federal Aviation Regulations (FAR) Part 21

Federal Aviation Regulations (FAR) Part 23

Federal Aviation Regulations (FAR) Part 39

Federal Aviation Regulations (FAR) Part 45

Federal Aviation Regulations (FAR) Part 91

Advisory Circular (AC) 91-67

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