variation in weight limitation may be presented as graphs in the performance section of the manual and included as limitations by specific reference in the limitations section of the AFM.
3. § 23.1585 Operating Procedures.
a. Explanation. Refer to GAMA Specification 1.
b. Electronic Checklist Displays.
(1) Background. Checklists, both hard copy and electronic displays, are a method used by manufacturers to provide (in part) the normal and emergency operating procedures required by § 23.1585. Section 23.1581 is also a pplicable for the manner and format of presentation.
(2) Display Content. For those airplanes with appr oved AFMs, the wide variety of configurations and corresponding flight manual supplements within a single model may establish a virtually unique set of checklist procedures for each individual airplane. The responsibility for electronic checklist display contents rests with the operator. A hard copy of the AFM should be available to the operator for reference.
(3) AFM Changes. Incorporation of STC’s could n ecessitate changes to the flight manual, flight manual supplements, or addition of new supplements. These supplements could require revision to the checklist for that particular airplane. Such changes should be made by the operator.
(4) Operator Revisions. Although it is not necessary for equipment manufacturers to store electronic checklist data in such a manner that it cannot be changed in the field, some equipment manufacturers have chosen to program checklist data in a manner that prevents field alternation. The operator would be responsible for ensuring the checklist data is revised as necessary upon installation of new/different equipment.
(5) Disclaimers. Electronic checklists are usually displayed on the same MFD as other electronic displays. Cert ain disclaimer statements may be appropriate. Presentation of a disclaimer statement each time the equipment is turned on will provide adequate notification to the pilot. This disclaim er should include statements that clearly state:
(i) Contents of the checklists are the responsibility of the operator
(ii) The approved AFM takes precedence and, for completeness, should be referred to as the primary information source.
(iii) The electronic checklist may not contain all the notes, cautions, and warnings associated with a procedure.
(6) Automatic Display. Automatic display of ap propriate checklists during conditions of engine failure, generator failure, and so forth, will require a review based upon the 167
specific application involved. Approval of the checklist content, malfunction prioritization, and operation is required.
4. § 23.1587 Performance Information.
a. Performance Information. This section contains the airworthiness performance information necessary for operation in compliance with applicable performance requirements of part 23, applicable special conditions, and data required by part 36. Additional information and data essential for implementing special operational requirements may be included. Performance information and data should be presented for the range of weight, altitude, temperature, airplane configurations, thrust rating, and any other operational variables stated for the airplane. This information should include a discussion of icing operations, loss of performance possible, and any information to aid in recognition of icing conditions that may exceed the certificated capabilities of the aircraft ice protection systems.
b. Normal, Utility, and Acrobatic Category Airplanes. Refer to GAMA Specification 1.
c. Turbine Airplanes and Commuter Category Airplanes.
(1) General. Include all descriptive informati on necessary to identify the precise configuration and conditions for which the performance data are applicable. Such information should include the complete model designations of airplane and engines, the approved flap, sweep, or canard settings, definition of installed airplane features and equipment that affect performance, together with the operative status thereof (for example, antiskid devices, automatic spoilers, and so forth). This section should also include definitions of terms used in the performance section (that is, IAS, CAS, ISA, configuration, net takeoff flight path, icing conditions, and so forth), plus calibration data for airspeed (flight and ground), Mach number, altimeter, ambient air temperature, and other pertinent information.
(2) Performance Procedures. The procedures, techniques, and other conditions associated with attainment of the flight manual performance data should be included.
Performance procedures may be presented as a performance subsection or in connection with a particular performance graph. In the latter case, a comprehensive listing of the conditions associated with the particular performance may serve the objective of "procedures" if sufficiently complete.
(3) Thrust or Power Setting. Thrust or power settings s hould be provided for at least takeoff and maximum continuous and the methods required to obtain the performance shown in the AFM. If appropriate, these data may be require d to be shown for more than one thrust setting parameter.
(4) Takeoff Speeds. The operational takeoff speeds V 1, VR, and V2 should be presented together with associated conditions. Section 23.1587(d)(10) requires the speeds be given in CAS. Since the flightcr ew flies IAS, the airspeeds should also be presented in IAS.
The V1 and VR speeds should be based upon "ground effect" calibration data; the V2 speeds should be based upon "free air" calibration data.
(5) Takeoff Distance. Takeoff distance should be shown in compliance with § 23.59.
(6) Climb Limited Takeoff Weight. The climb limited takeoff weight, that is the most limiting weight showing compliance with § 23.67, should be provided.
(7) Miscellaneous Takeoff Weight Limits. Takeoff weight limits, for any equipment or characteristic of the airplane configuration which imposes an additional takeoff weight restriction, should be shown (that is, tire speed limitations, brake energy limitations, and so forth).
(8) Takeoff Climb Performance. For the prescribed takeoff climb airplane configurations, the climb gradients should be presented together with associated conditions. The scheduled climb speed(s) should be included.
(9) Takeoff Flight Path Data. The takeoff flight paths of § 23.61 or performance information necessary to enable construction of such paths, together with associated conditions (that is, procedures, speed schedules), should be presented for the configurations and flight path segments existing between the end of the prescribed takeoff distance and the point of attaining the en route climb configuration airspeed or 1500 feet, whichever is higher.
(10) En Route Climb Data. The climb gradients prescribed in § 23.67 should be presented together with associated conditions, including the speed schedule used.
(11) Balked Landing Climb Limited Landing Weight. The climb limited landing weight that is the most limiting weight showing compliance with § 23.77.
(12) Approach Climb Limited Landing Weight. The climb gradient determined in § 23.67(e)(3) should be presented. The required climb gradient may limit the landing weight.
(13) Landing Approach Speeds. The scheduled speeds associated with the approved landing distances should be presented together with associated conditions.
(14) Landing Distance. The landing distance from a height of 50 feet should be presented together with associated ambient temperature, altitude, wind conditions, and weights up to the maximum landing weight. Operational landing distance data should be presented for smooth, dry, and hard-surfaced runways. At the option of the applicant, with concurrence by the FAA, additional data may be presented for wet or contaminated runways and for other than smooth, hard-surfaced runways.
(15) Headwinds/Tailwinds. Where specified within § 23.1587, the effect of headwinds and tailwinds must be defined. When the performance gradient is positive, use 50 percent of the headwind component and 150 percent of the tailwind component. When the 169
performance gradient is negative, use 150 percent of the headwind component and 50 percent of the tailwind component.
5. § 23.1589 Loading Information. Refer to GAMA specification 1.
Appendix 1. Power Available
1. General. The purpose of this appendix is to provide guidance regarding the power considerations for various kinds of powerplants. The power output of each airplane/engine configuration requires special considerations when determining test day performance corrections and providing the performance expansions for the AFM. The types of powerplants discussed in this appendix are:
a. Reciprocating Engines.
(1) Normally aspirated engine with a fixed pitch propeller;
(2) Normally aspirated engine with a constant speed propeller; and
(3) Turbocharged engine with a constant speed propeller.
b. Turbopropeller Engines.
2. Reciprocating Engines.
a. Power Charts. The horsepower being developed by reciprocating engines is usually identified by horsepower charts that are provided by the engine manufacturer. These charts are developed from results of ground runs using a brake-type dynamometer in a test facility and may have no direct correlation to any particular airplane or flight condition. The variations of power with altitude and temperature are the result of theoretical relationships involving air density, fuel/air ratios, and so forth. These charts nearly always assume a “b est power” fuel to air ratio that can rarely be consistently used in service under normal operating conditions. Many installations, for example, intentionally use fuel to air ratios that are on the fuel-rich side of best power so that the engine will not overheat. Providing sufficient cooling airflow ov er each cylinder to ensure adequate cooling may be more difficult than cooling with a rich fuel mixture. These horsepower charts were also developed while maintaining a constant temperature on each cylinder. This is not possible in service. The charts are developed assuming the following:
(1) There is no ram airflow due to movement through the air; or
(2) There are not losses due to pressure drops resulting from intake and air filter design; or
(3) There are no accessory losses.
b. Chart Assumptions. Regardless of the test stand conditions that are not duplicated in service, it is necessary to assume that each given pressure altitude temperature, engine speed, and manifold pressure combination will result in horsepower that can be determined from the engine power chart.
To accomplish this requires certain procedures and considerations.
c. Tolerances. Each engine power chart specifies a horsepower tolerance from rated horsepower.
These are commonly ±2 ½ percent, +5 percent, -2 percent, or +5 percent, -0 percent. This means that with all the variables affecting power being held constant (that is, constant manifold pressure, engine speed, temperature, and fuel to air ratio), the power could vary this much from engine to engine. For this reason, it is appropriate to account for these variations. Calibration of the test engine(s) by the engine manufacturer is one way to accomplishing this. During engine calibration, the test engine is run on a test stand at the engine manufacturer’s facility to identify how it compares with the power A1-1
output at conditions under which it was rated. The result is a single point comparison to the rated horsepower.
d. Test Day Power.
(1) Calibrated Engines. If an engine, for example, is rated at 200 BHP, the calibration results might show the particular serial numbered engine to develop 198.6 BHP. This is 0.7 percent below the rated power. For this engine, each of the horsepower values obtained from the engine manufacturer’s chart should be adjusted downward by 0.7 percent to obtain test day horsepower.
(2) Uncalibrated Engines. If the engine is not calibrated, an acceptable method of accounting for the unknown factors is to assume that the test engine is putting out rated horsepower plus the plus tolerance. For example, if the rated horsepower was 350 and the tolerance was ±2 ½ percent, test day sea level chart horsepower would be assumed to be 350 + .025 (350), or 358.8.
(3) Humidity. Section 23.45(e) requires performance to be based on 80 percent relative humidity on a standard day. Experience has shown that conditions such as 80 percent relative humidity on a standard day at sea level have a very small effect on engine power because this condition results in a very low specific humidity. The engine is affected directly by specific humidity (pounds of water per pounds of air) rather than relative humidity. For test day power, dry air should be assumed unless the applicant has an approved method for measuring and determining the effect of humidity.
e. Chart Brake Horsepower. A chart brake horsepower (BHPc) should be determined for expansion of the flight test data in the AFM. BHPc is the horsepower at a particular pressure altitude, manifold pressure and r.p.m. Appropriate inlet temperature corrections should be applied, in accordance with the manufacturer’s engine power chart. An 80 percent relative humidity correction should be applied if the engine manufacturer has an acceptable method and the correction is significant.
f. Variations in Methods. Peculiarities of the various types of reciprocating engines require special considerations or procedures to determine installed power. These procedures are discussed in subsequent paragraphs.
3. Normally Aspirated Engines with Constant Speed Propellers.
a. Manifold Pressure Versus Altitude. As a first step to determine installed horsepower, flight tests should be conducted to determine manifold pressure versus pressure altitude for the engine installation. The test manifold pressures would be compared to the engine manufacturer’s chart values, as shown on Figure A1-1. Figure A1-1 shows an example of test manifold pressure and chart manifold pressures versus pressure altitude. In this example, the observed manifold pressures are lower than the chart values. This means that the induction system pressure losses exceed the ram pressure rise. An induction system in which manifold pressures exceed the zero ram chart values would reflect an efficient induction system. The term chart brake horsepower indicates that the horsepower values have yet to be corrected for inlet temperature conditions.
b. Example Calculation. The overall corrections to determine installed test day brake horsepower and chart brake horsepower (BHPc) to be used in the expansion of performance would be as follows (refer to Figure A1-1):
A1-2
~- ~- Known: Pressure Altitude..............................................................4,000 feet Manifold Pressure............................................................24.9 in Hg.
Outside Air Temperature.................................................+55 ºF Inlet Temperature............................................................+63 ºF
Engine Speed...................................................................2,650 r.p.m.
Engine Calibration...........................................................-0.7 % Engine Tolerance.............................................................±2 ½ %
Calculated Test Day BHP for a Calibrated Engine:
Standard Temperature @ 4,000 ft.....................................................44.7 ºF Installed Chart Brake Horsepower....................................................335 BHP (from Figure A1-1) Engine Calibration Correction = (335)(-.007)...................................-2.3 BHP Correcting for Inlet Temperature 460 44.7Test Day BHP = (335-2.3) ........................................326.8 BHP 460 63.0 Calculated Test Day BHP for an Uncalibrated Engine:
Standard Temperature @ 4,000 ft.....................................................44.7 ºF Installed Chart Brake Horsepower....................................................335 BHP (from Figure A1-1) 460 44.7Test Day BHP =[335 + .025(335)] ............................337.3 BHP 460 63 Calculated BHPc for Test Day Density Altitude (Hd):
Hd at 4,000 ft. and 55 ºF..................................................................4,670 ft.
Installed BHPc (from Figure A1-1)........................................................326 BHP Standard Temperature at 4,670 ft.....................................................42 ºF Correcting for Inlet Temperature Rise 460 42BHPc = 326 ........................................................323.4 BHP 460 42 8 A1-3
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20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 11/16/2011 AC 23-8C Figure A1-1 – Brake Horsepower Versus Pressure Altitude A1-4
PRESSURE ALTITUDE
IN FEET
SEA LEVEL 20 22 24 26 28 3018 MANIFOLD PRESSURE - IN.H.g.
240 280 320 360 400 BRAKE HORSEPOWER - BHPc
FULL THROTTLE MANIFOLD PRESSURE vs
PRESSURE ALTITUDE
FULL THROTTLE, TEST MANIFOLD
PRESSURES AT VY (OBTAINED FROM COOLING CLIMB
OR CLIMB PERFORMANCE DATA)
FULL THROTTLE ZERO
RAM CHART MANIFOLD PRESSURE 2650 RPM
FULL THROTTLE
INSTALLED CHART BRAKE HORSEPOWER 2650 RPM
FULL THROTTLE ZERO RAM
CHART BRAKE HORSEPOWER 2650 RPM
~- Calculated Test Day BHPc for the AFM Expansion:
For the Same Conditions as Test Day,............................................335 BHP BHP (from Figure A1-1)........................................................................335 BHP Correcting for Inlet Temperature, expansion 460 44.7 ..............................................................329.1 BHP BHP – 335 460 63
4. Turbocharged Engines with Constant Speed Propellers.
a. Manifold Pressure Versus Altitude. From flight tests, it is appropriate to plot manifold pressure versus pressure altitude used to demonstrate satisfactory cooling and climb performance demonstrations. The engine manufacturer’s chart brake horsepower should be entered at these manifold pressure values. The result is the chart br ake horsepower to be utilized in data expansion.
For some installations, the manifold pressure and fuel flows are limited by the airplane manufacturer’s design schedule. For these, the full th rottle values must be identified. Whenever the manifold pressures and fuel flows must be manually set to a schedule, corresponding limitations must be established.
b. Horsepower. Refer to Figure A1-2 for an illustration of manifold pressure and horsepower versus pressure altitude. It is rare for the horsepower values to be constant below the critical altitude. The horsepower ratings are not necessarily limited and it is common to observe chart horsepower values at the intermediate altitudes higher than rated power. As with normally aspirated engines, the term chart brake horsepower indicates that the horsepower values have yet to be corrected for inlet temperature conditions. The corrections for temperature are usually greater for turbocharged than normally aspirated. A 1 percent decrease in power for each 10 ºF increase in temperature above standard temperature conditions at a constant specific fuel consumption (SFC) is common. The apparent effects for a particular installation could be more or less than this. Manufacturer’s data for the particular engine should be used.
c. Example Calculation. The overall corrections to determine installed test brake horsepower and brake horsepower to be used in the expansion of performance would be as follows (refer to Figure A1-2):
Known: Pressure Altitude.....................................................9,500 feet Manifold Pressure...................................................44.3 in. Hg.
Outside Air Temperature........................................53.0 ºF Compressor Inlet Temperature...............................67 ºF Engine Speed..........................................................2,575 r.p.m.
Engine Calibration..................................................+1.7% Engine Tolerance....................................................±2 1/2%
A1-5
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I ~) 24000 22000 20000 18000 16000 14000
PRESSURE ALTITUDE - 12000 FEET 10000 8000 6000 4000 2000 SEA LEVEL MANIFOLD PRESSURE vs PRESSURE ALTITUDE MANIFOLD PRESSURE - In.H.g.
BRAKE HORSEPOWER vs PRESSURE ALTITUDE BRAKE HORSEPOWER - BHPc 36 37 38 39 40 41 42 43 44 45 46 290 300 310 320 330 340 350 360
FULL THROTTLE
MANIFOLD PRESSURE OBSERVED
DURING COOLING CLIMBS AND
PERFORMANCE CLIMBS
INSTALLED CHART
BRAKE HORSEPOWER 2575 RPM 11/16/2011 AC 23-8C Appendix 1 Figure A1-2 - Turbocharged Brake Horsepower Versus Altitude A1-6
Appendix 1 Calculated Test Day BHP for a Calibrated Engine:
Standard Temperature @ 9,500 ft.....................................................25.1 ºF Power Correction Due to Temperature at 1%/10 ºF........................................................................................-4.2% (Temperature rise = 67º -25.1 ºF) Installed Chart Brake Horsepower (from Figure A1-2)...................................................................................351 BHP Engine Calibration Correction (351)(.017).......................................+5.97 BHP Test BHP = (351 + 5.97) - (.042)(356.97)......................................332.1 BHP Calculated Test Day BHP for an Uncalibrated Engine:
Standard Temperature @ 9,500 ft.....................................................25.1 ºF Power Correction at 1%/10 ºF...........................................................-4.2%
Installed Chart Brake Horsepower351
(from Figure A1-2) Test BHP = 351 - (351)(.042) + 351(.025)......................................335.3 Calculated BHPc for Test Day Density Altitude (Hd):
Hd at 9,500 ft and 53 ºF....................................................................11,280 ft Installed BHPc (from Figure A1-2).........................................................350 BHP Power Correction Due to Inlet Temperature Rise at 1%/10 ºF (temperature rise = 14 ºF)..................................................................-1.4% BHPc = 350-(350)(.0233)..................................................................341.8 BHP Calculated BHPc for the AFM Expansion:
For the Same Conditions as Test Day,...............................................351 BHP BHPc (from Figure A1-2)
Temperature Correction to BHPc =...................................................326.5 BHP 350-(.042)(351)
5. Normally Aspirated Engines with Fixed Pitch Propellers. (Reserved).
6. Turbopropeller Engines.
a. Power Measurement. Turbopropeller engines (turboprops) are gas turbine engines that drive a propeller. Power output is a function of the gas tu rbine airflow, pressure, and temperature. Power measurement is made by measurement of the propeller shaft speed and torque, from which the shaft horsepower can be obtained by a simple calculation. Torque is measured by an integral device that may be mechanical, hydraulic, or electrical and connects to the indicator required by Part 23, § 23.1305(m). Shaft horsepower is the same as brake horsepower, that is, the power developed at the propeller shaft. The total thrust horsepower, or e quivalent shaft horsepower (ESHP) is the sum of the shaft horsepower and the nominal horsepower equivalent of the net exhaust thrust.
A1-7
Appendix 1
b. Power Available. The prediction of power available is obtained from the engine manufacturer as a computer program. Each installation must be evaluated to identify:
Generator Loads (all engine and one engine inoperative) Bleed Air Extractions (with and without ice protection) Accessory Pad Extractions
Engine Air Inlet Efficiency (with and without ice protection) Engine Exhaust Efficiency Effect of Specific Humidity
With these values as input to the computer program, installed power available and fuel flows at various airspeeds, temperatures, and altitudes can be calculated.
A1-8