23.1023 Oil radiators (Original)
CAR 3 Cross-reference: 3.572
ADC Cross-reference: 5.37
No specific policy is available as of December 31, 2002.
23.1027 Propeller feathering system (Amendment 23-43)
CAR 3 Cross-reference: None
ADC Cross-reference: 5.38
Related Material
AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes
Paragraph 23.1027(a)
ADC Cross-reference: 5.38(a)
No specific policy is available as of December 31, 2002.
Paragraph 23.1027(b)
ADC Cross-reference: 5.38(b)
No specific policy is available as of December 31, 2002.
Paragraph 23.1027(c)
ADC Cross-reference: 5.38(c)
No specific policy is available as of December 31, 2002.
Paragraph 23.1027(d)
ADC Cross-reference: 5.38(d)
No specific policy is available as of December 31, 2002.
COOLING
23.1041 General (Amendment 23-51)
CAR 3 Cross-reference: 3.581
ADC Cross-reference: 5.39
When is testing required to show compliance with § 23.1041?
Sections 23.1043, 23.1045, and 23.1047 require testing to show compliance with § 23.1041.
What changes to an airplane would require testing to show compliance with § 23.1041?
Changes to an airplane that would require testing to show compliance with § 23.1041 could include, but are not limited to, the following:
1. Engine horsepower increase;
2. Nacelle changes, including cooling inlet modifications and blockage;
3. Adding or changing engine accessories such as turbochargers, generators, oil coolers, etcetera;
4. Changing the operating temperature limits of components in the nacelle; and
5. Propeller changes affecting climb or cruise performance.
What should be instrumented during the cooling tests on changes to airplanes?
The tests should be conducted to show the changed components remain within their temperature limits. During the testing, if negative impacts on other components are found, additional testing may be warranted to investigate these effects.
What altitudes are typically used for demonstrating compliance with the cooling requirements for reciprocating engine powered airplanes?
For reciprocating engines, cooling climb tests are typically commenced at pressure altitudes below 5,000 feet. The applicant should choose test conditions that are the most adverse for demonstrating engine and engine component cooling for the installation.
Related Material
AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes 115
23.1043 Cooling tests (Amendment 23-51)
CAR 3 Cross-reference: 3.582, 3.583, 3.584, 3.585
ADC Cross-reference: 5.40
Paragraph 23.1043(a)
ADC Cross-reference: 5.40(a)
What are the typical means of complying with § 23.1043?
In general, the demonstration of compliance with this section requires analysis to identify areas of concern and instrumentation requirements and flight tests to demonstrate compliance. The applicant must identify all critical components (electronic components, actuators, etc.), fluids (engine oil, hydraulic fluid, etc.), and structures (primary composite structural elements, vibration isolators, etcetera) that have temperature limits.
The limits are typically based on component qualification testing. Each limit may be expressed as a fluid temperature, surface temperature, or environmental temperature and may have associated time limits. Instrumentation should be installed to provide data needed to show the corrected temperature for each critical component, fluid, and structure remains below the identified limit.
Are there any special considerations for special purpose, restricted category, singleengine agricultural airplanes using the normal category requirements of part 23 as a certification basis?
For these aircraft, conduct engine cooling test according to AC 23-8B, except as follows:
After the temperature has stabilized for the pre-takeoff holding condition on the taxiway, feather the propeller and record the data until the temperatures stabilize.
NOTE: This simulates normal agricultural operational engine running loading conditions. These criteria can be disregarded if the propeller is not feathered during normal agricultural operations on the ground.
Are there any special considerations for certificating winterization kits?
Winterization kits modify an airplane for operation in cold weather environments. These kits typically block or baffle air inlets to decrease mixing cold air in the engine compartments and keep the temperatures of fluids and components from falling below operating range. These kits can allow certification to lower ambient temperature operations than the standard 38 ºC (100 ºF). These limits must be reflected in the Airplane Flight Manual and placards on the equipment to indicate when the equipment should be removed. Additional guidance is available in paragraph 246 of AC 23-8B.
Related Material
AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes
Paragraph 23.1043(b)
ADC Cross-reference: 5.40(b)
No specific policy is available as of December 31, 2002.
Paragraph 23.1043 (c)
ADC Cross-reference: 5.40(c)
No specific policy is available as of December 31, 2002.
Paragraph 23.1043 (d)
ADC Cross-reference: 5.40(d)
No specific policy is available as of December 31, 2002.
Related Material
AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes
23.1045 Cooling test procedures for turbine engine powered airplanes (Amendment 23-51)
CAR 3 Cross-reference: None
ADC Cross-reference: 5.41, 5.41(a), 5.41(b), 5.41(c), 5.41(d)
Related Material
AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes
Paragraph 23.1045(a)
ADC Cross-reference: 5.41(a)
No specific policy is available as of December 31, 2002.
Paragraph 23.1045(b)
ADC Cross-reference: 5.41(b)
No specific policy is available as of December 31, 2002.
Paragraph 23.1045(c)
ADC Cross-reference: 5.41(c)
No specific policy is available as of December 31, 2002.
23.1047 Cooling test procedures for reciprocating engine powered airplanes (Amendment 23-51)
CAR 3 Cross-reference: 3.587
ADC Cross-reference: 5.41, 5.41(a), 5.41(b), 5.41(c), 5.41(e)
No specific policy is available as of December 31, 2002.
Related Material
AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes
LIQUID COOLING
23.1061 Installation (Amendment 23-43)
CAR 3 Cross-reference: None
ADC Cross-reference: 5.42
Paragraph 23.1061(a)
ADC Cross-reference: 5.42(a)
No specific policy is available as of December 31, 2002.
Paragraph 23.1061(b)
ADC Cross-reference: 5.42(b)
No specific policy is available as of December 31, 2002.
Paragraph 23.1061(c)
ADC Cross-reference: 5.42(c)
No specific policy is available as of December 31, 2002.
Paragraph 23.1061(d)
ADC Cross-reference: 5.42(d)
No specific policy is available as of December 31, 2002.
Paragraph 23.1061(e)
ADC Cross-reference: 5.42(e)
No specific policy is available as of December 31, 2002.
Paragraph 23.1061(f)
ADC Cross-reference: 5.42(f)
No specific policy is available as of December 31, 2002.
23.1063 Coolant tank tests (Original)
CAR 3 Cross-reference: None
ADC Cross-reference: 5.43
Paragraph 23.1063(a)
ADC Cross-reference: 5.43(a)
No specific policy is available as of December 31, 2002.
Paragraph 23.1063(b)
ADC Cross-reference: 5.43(b)
No specific policy is available as of December 31, 2002.
INDUCTION SYSTEM
23.1091 Air induction system (Amendment 23-51)
CAR 3 Cross-reference: 3.605
ADC Cross-reference: 5.44
Related Material
AC 20-135, Powerplant Installation and Propulsion System Component Fire Protection Test Methods, Standards, and Criteria
Paragraph 23.1091(a)
ADC Cross-reference: 5.44(a)
No specific policy is available as of December 31, 2002.
Paragraph 23.1091(b)
ADC Cross-reference: 5.44(b)
No specific policy is available as of December 31, 2002.
Related Material
AC 23-2, Flammability Tests
Paragraph 23.1091(c)
ADC Cross-reference: 5.44(c)
What is considered a hazardous quantity in § 23.1091(c)?
A hazardous quantity is defined as one that if ingested into the engine inlet would cause the engine to exceed its operational limitations, cause a significant loss of power, or otherwise cause the engine to operate in an unsafe condition.
Related Material
AC 20-124, Water Ingestion Testing for Turbine Powered Airplanes
23.1093 Induction system icing protection (Amendment 23-51)
CAR 3 Cross-reference: 3.606
ADC Cross-reference: 5.45
Is an airplane required to comply with § 23.1093 if it is not being certificated to fly in icing conditions?
Yes, compliance with § 23.1093(b) for induction system icing protection is required for all normal, utility, acrobatic, and commuter category airplanes certificated under part 23 even if the airplane is not being certificated for flight in icing conditions (§ 23.1419 compliance). Service experience has shown that airplanes can inadvertently encounter icing conditions even if the airplane is not approved for flight into icing conditions. This is particularly true for turbine engine powered airplanes, which typically have a greater operating flight envelope than reciprocating engine powered airplanes. These requirements are also those demonstrated during engine certification (reference 14 CFR part 33, subpart E, § 33.68, Induction system icing, for turbine aircraft engines).
What other icing related sections of 14 CFR part 23 cover the propulsion systems?
Sections 23.901(d)(2), 23.929, and 23.975(a)(1) address engine ice ingestion capability, engine installations including propellers, and fuel tank venting, respectively.
Are all icing related sections of 14 CFR part 23 that cover the propulsion systems required for airplanes not being certificated to fly in icing conditions?
Airplanes not being certified for flight into icing conditions according to § 23.1419 do not have to demonstrate compliance with § 23.929.
Are there any special considerations for special purpose, restricted category, singleengine agricultural airplanes using the normal category requirements of part 23 as a certification basis?
An exemption to the requirements of § 23.1093 is possible for single-engine piston or turbopropeller airplanes certificated under 14 CFR part 21, § 21.25(a), for special purpose agricultural operations. A limitation in the Airplane Flight Manual, such as “Operation of the airplane in visible moisture below 40 °F is prohibited,” will be enough to address this regulation for these non-standard category airplanes.
What methods can be used to show compliance with § 23.1093?
Compliance with § 23.1093 can be shown using an appropriate combination of the methods listed and described below.
1. Compliance with part 33 icing requirements
2. Similarity and service experience
3. Analysis
4. Ground testing
5. Flight testing with an airborne icing tanker
6. Flight testing in natural icing conditions
How can the part 33 engine certification be used to demonstrate compliance?
Engine certification to part 33 does not fully address all the part 23 engine installation requirements. For example, part 33 engine certification does not address snow ingestion.
It is the responsibility of the airplane applicant and not the engine manufacturer to show compliance with the part 23 induction system ice protection requirements.
An applicant seeking airplane certification should coordinate the installation of an engine with the engine manufacturer. The engine manufacturer should be able to identify critical points, conditions, and operational requirements that may need to be addressed when showing compliance with the installation requirements. Engine type certification data can be used as the basis for reducing design risk, analysis, and testing when showing compliance with § 23.1093. The airplane applicant should evaluate the engine type certification data and demonstrate how the data is applicable to the particular installation.
For example, the use of an inlet system recommended by the engine manufacturer would still require installation substantiation to show compliance with part 23 requirements.
How can similarity and service experience be used for compliance?
The use of similarity and service experience is appropriate to lessen the design risk associated with an installation. Once an applicant has developed data on an installation, the applicant may then use this data, when suitable, for substantiation on later projects with similar installations. It is common and proper for an applicant to base analytical methods and test point definitions on experience and testing from previous, similar certification programs performed by the applicant. Certification is based on the analysis and testing of an airplane’s type design. Because of this, it is difficult to show similarity to an airplane configuration certified by another applicant without direct access to the type design data used for that certification.
Even if previous experience and data are used, each inlet/engine installation and the associated operating characteristics can be different and should be considered individually. Therefore, it is not appropriate to use similarity or service experience by itself to demonstrate compliance to the § 23.1093 requirements. Rather, such means as 124