Aircraft Design, Certification, and Airworthiness  process, each part is inspected to ensure that it has been built  exactly according to the approved design. This inspection is  called a conformity inspection.  The FAA certifies three types of aviation products: aircraft,  aircraft engines, and propellers. Each of these products  has been designed to a set of airworthiness standards.  These standards are parts of Title 14 of the Code of  Federal Regulations (14 CFR), published by the FAA. The  airworthiness standards were developed to help ensure that  aviation products are designed with no unsafe features.  Different airworthiness standards apply to the different  categories of aviation products as follows:  When the aircraft is complete, with the airframe, engine, and  propeller, it is inspected and the FAA issues an airworthiness  certificate for the aircraft. Having an airworthiness  certificate means the complete aircraft meets the design and  manufacturing standards, and is in a condition for safe flight.  This airworthiness certificate must be carried in the aircraft  during all flight operations. The airworthiness certificate  remains valid as long as the required maintenance and  inspections are kept up to date for the aircraft.  Airworthiness certificates are classified as either “Standard”  or “Special.” Standard airworthiness certificates are white,  and are issued for normal, utility, acrobatic, commuter, or  transport category aircraft. They are also issued for manned  free balloons and aircraft designated as “Special Class.”  Special airworthiness certificates are pink, and are issued  for primary, restricted, and limited category aircraft, and  light sport aircraft. They are also issued as provisional  airworthiness certificates, special flight permits (ferry  permits), and for experimental aircraft.  More information on airworthiness certificates can be found  in Chapter 9, in 14 CFR parts 175-225, and also on the FAA  website at www.faa.gov.  In order to understand the operation of the major components  and subcomponents of an aircraft, it is important to  understand basic aerodynamic concepts. This chapter briefly  introduces aerodynamics; a more detailed explanation can be  found in Chapter 5, Aerodynamics of Flight.  Four forces act upon an aircraft in relation to straight-and­ level, unaccelerated flight. These forces are thrust, lift,  weight, and drag.  [Figure 3-1]  Thrust is the forward force produced by the powerplant/  propeller. It opposes or overcomes the force of drag. As a  general rule, it is said to act parallel to the longitudinal axis.  This is not always the case as explained later.  Drag is a rearward, retarding force and is caused by disruption  of airflow by the wing, fuselage, and other protruding objects.  Drag opposes thrust and acts rearward parallel to the relative  wind.  Aircraft, aircraft engines, and propellers can be manufactured  one at a time from the design drawings, or through an FAA  approved manufacturing process, depending on the size and  capabilities of the manufacturer. During the manufacturing  Light sport aircraft are not designed according to FAA  airworthiness standards. Instead, they are designed to a  consensus of standards agreed upon in the aviation industry.  The FAA has agreed the consensus of standards is acceptable  as the design criteria for these aircraft. Light sport aircraft do  not necessarily have individually type certificated engines  and propellers. Instead, a TC is issued to the aircraft as a  whole. It includes the airframe, engine, and propeller.  The FAA issues a Type Certificate (TC) for the product  when they are satisfied it complies with the applicable  airworthiness standards. When the TC is issued, a Type  Certificate Data Sheet (TCDS) is generated that specifies  the important design and operational characteristics of the  aircraft, aircraft engine, or propeller. The TCDS defines the  product and are available to the public from the FAA website  at www.faa.gov.  Some aircraft are considered “special classes” of aircraft and  do not have their own airworthiness standards, such as gliders  and powered lift. The airworthiness standards used for these  aircraft are a combination of requirements in 14 CFR parts  23, 25, 27, and 29 that the FAA and the designer have agreed  are appropriate for the proposed aircraft.  •  Normal, Utility, Acrobatic, and Commuter Category  Airplanes- 14 CFR part 23  •  Transport Category Airplanes—14 CFR part 25  •  Normal Category—14 CFR part 27  •  Transport Category Rotorcraft—14 CFR part 29  •  Manned Free Balloons—14 CFR part 31  •  Aircraft Engines—14 CFR part 33  •  Propellers—14 CFR part 35  Lift and Basic Aerodynamics  A Note About Light Sport Aircraft  3-2 