(C) Hover performance charts both IGE and OGE with instructions for their use.
(D) For turbine-powered helicopters in all categories, a power assurance check chart.
(E) A statement of the maximum crosswind and downwind components that have been demonstrated as safe for operation both IGE and OGE.
(v) Miscellaneous Performance Data. Any performance information or data not covered in AC 27.1587.a.(3) (iv)(A) through (E) above, but considered necessary or desirable to enhance safety or to enable application of the operating regulations, should be included.
(vi) Flightcrew Notes. Recommend that provisions be made in the "unapproved" portion of the RFM for inclusion of information and data of a type that is useful or desirable for operation of the rotorcraft; but is not approved by FAA/AUTHORITY. (Material in this section should be consistent with material in the approved portion of the manual.)
b. Procedures. None.
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AC 27.1587B. § 27.1587 (AMENDMENT 27-51) PERFORMANCE INFORMATION.
a. Explanation. Amendment 27-51 changed the term "height-speed" to "heightenvelope" at amendment 29-39.
effect. Por puduses The is Ac, tentaring in en recodie ain there on remains in equivalent.
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AC 27-1B, Chg 4 3/31/2014 AC 27.1589. § 27.1589 LOADING INFORMATION.
a. Explanation. Control of the rotorcraft weight and balance is an operational tunction and is the responsibility of the operator. However, instructions necessary to enable loading of the rotorcraft within the established limits of weight and center of gravity and to maintain the loading within such limits are required by the operating regulations, and inclusion of such loading instructions in the Rotorcraft Flight Manual is required by this rule. Approved loading instructions, therefore, must be presented in the Rotorcraft Flight Manual and, at the option of the applicant, may be included in the approved portion or in the unapproved portion.
b. Procedures.
(1) For the purpose of the flight manual, distinction is made here between the loading instructions required by the certification requirements of Part 27 and the weight and balance data required by the operating requirements. The former prescribed information is applicable to the rotorcraft type and is subject to FAA/AUTHORITY approval as flight manual material.
(2) For compliance with the noted requirements, it is necessary for the applicant to develop weight and balance data and loading instructions as necessary to satisfy the needs of both certification and operation. In order to consolidate in one document information on rotorcraft loading, it is recommended that the weight and balance data be developed to include appropriate loading instructions, and that both be included in the Rotorcraft Flight Manual as an "unapproved" section entitled "Weight and Balance." Such a section should include the following statement as a note: "In accordance with FAA/AUTHORITY procedures, the detail weight and balance data of this section are not subject to FAA/AUTHORITY approval. The loading instructions of this section, however, have been approved by FAA/AUTHORITY as satisfying all requirements for instructions on loading of the rotorcraft within approved limits of weight and center of gravity and on maintaining the loading within such limits."
(3) For initial approval of the manual, an actual or specimen weight and balance section should be submitted for evaluation and approval of the loading instructions. Weight and balance data for each particular rotorcraft need not be submitted for approval as flight manual material unless a substantive change is made to the approved loading instructions.
(4) The weight and balance material outlined below is believed to be adequate for rotorcraft with conventional loading and fuel-management techniques. For rotorcraft which necessitate redistribution of fuel (other than normal consumption) to maintain loading within prescribed limits, the material should be amplified as necessary.
Weight Limits. A list and explanation, where necessary, of all fixed-weight limitations should be included.
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(ii) Center of Gravity Limits. The approved center of gravity ranges should be presented with due accounting for landing gear position.
(II) Dimensions and Datum Line Locations. The dimensions and relative location of rotorcraft features associated with weighing and loading of the rotorcraft and with weight and balance computations should be described and/or illustrated.
(iv) Equipment List. The rotorcraft should be defined or described sufficiently to identify the presence or absence of optional systems, features, or installations that are not readily apparent. In addition, all other items of fixed and removable equipment included in the empty weight should be listed.
(v) Fuel and Other Liquids. Fuel and other liquids, including passenger-service liquids that are included in the empty weight, should be identified and listed together with information necessary to enable ready duplication of the particular condition.
(vi) Weight Computations. Computations of the empty weight and empty-weight CG location should be included.
(vii) Empty Weight and Empty-Weight Center of Gravity Location.
Statement of these values should be included.
(vili) Loading Schedule. Loading schedule should be included, if appropriate.
(ix) Loading Instructions. Complete instructions relative to the loading procedure, or to use the loading schedule, should be included.
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CHAPTER 3
AIRWORTHINESS STANDARDS
NORMAL CATEGORY ROTORCRAFT
MISCELLANEOUS GUIDANCE (MG) AC 27 MG 1. CERTIFICATION PROCEDURE FOR ROTORCRAFT AVIONICS EQUIPMENT.
a. Pretest Requirements.
(1) General. This test guideline has been prepared as an aid in the evaluation of rotorcraft avionics (aviation electronics) equipment installations. The criteria presented are not exclusive, but are offered as one method of evaluating design practice and performance. Consider the testing and qualification of an electronic installation as consisting of three phases: preinstallation, ground, and flight. The amount of testing necessary during each phase will vary with the amount of testing performed on previous phases. For example, if a system is produced under a TSOA, pre-installation performance relative to TSO functions is likely substantiated. Therefore, the ground and flight test to assess these functions may be able to be reduced. However, a TSOA does not mean that the specific system meets installed performance requirements per 14 CFR part 27. In addition, a thorough ground testing program should result in reduction in necessary flight testing. When the operating or airworthiness regulations require a system to perform its intended function, we strongly recommend the use of TSO'd equipment or the submission of data substantiating the equipment performance.
(2) Regulatory References. Sections 27.1301 and 27.1309 (through Amendment 27-19).
(3) System Design. Sufficient data should accompany systems or equipment presented for installation approval, when not qualified by TSO or other approval means, to substantiate the design acceptability.
(1) Operation of Controls. The operation of controls intended for use during flight, in all possible position combinations and sequences, should not result in a condition that would be detrimental to the continued safe performance of the system.
(Il) Electrical Shock. Design systems to minimize the risk of dangerous electrical shock under all probable conditions.
(III) Fire Hazard. The design of the system should be such that all components meet the applicable fire and smoke protection requirements of §§ 27.853 and 27.863. Cables and equipment for installation in designated fire zones used during emergency procedures should be fire resistant.
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AC 27-1B, Chg 7 2/4/2016
(iv) Plugs and Cables. Connector pins for sensitive signal circuits should not be adjacent to pins used for ac power circuits. If redundant wiring is used to comply with systems regulations such as § 27.1309, the wires should be routed through separate plugs or cables with as much physical separation as practicable. The system design should eliminate possible incorrect mating of plugs. Minimize electromagnetic interference by using cable grounding and shielding techniques.
(4) System Performance. Where the operating or airworthiness regulations require a system to perform its intended function, and when the equipment is not qualified by TSO or other approval means, performance data furnished to the FAA AUTHORITY can reduce the installed performance testing. The appropriate TSO minimum performance standard may be useful as a guide.
(i) Environment. An appropriate means for environmental testing is set forth in Radio Technical Commission for Aeronautics (RTCA) Document DO-160. Applicants should submit test reports showing that the laboratory-tested categories, such as temperature, vibration, altitude, etc., are compatible with the environmental demands placed on the rotorcraft.
(ii) Failure Analysis. Section 27.1309(b) requires consideration of system malfunctions or failures.
(5) Installation Design.
(i) Mechanical Installation. Installations should ensure compliance with airworthiness regulations and comply with the equipment manufacturer's recommendations. The designer should observe good engineering practices in specifying material type, thickness, fastener type, edge distance, and attachment to the equipment rack. By analysis or static tests, the mounted equipment should be shown to withstand the inertia forces of §§ 27.561 (b)(3) and 27.337. Refer to AC 43.13-2 (current version) for static test procedures.
(ii) Arrangement and Visibility. The mounting position of all instruments, switches, position labels, and control heads should make them plainly visible to the pilot while in his normal, panel-facing position and under all cockpit lighting conditions likely to occur. TSO approval does not assure instruments will be acceptable in a particular cockpit installation or for all lighting conditions. The instruments, switches, and placarding must be free from reflections. Malfunction annunciation devices should be conspicuous and clearly visible to the pilot. (See §§ 27.1321, 27.771, 27.1381,
27.1555(a) and AC 20-69.)
(iii) Load Analysis.
(A) Power sources. It should be determined whether the electrical power source capacity is adequate for the system installation under all foreseeable operating conditions including engine failure on multiengine rotorcraft. Apply system load Page MG 1 -2
reductions or increase power source capacity, if necessary, to assure compatibility between load and source. If duplicate systems are required, power them from separate buses.
(B) Navigation course deviation circuit loading. It should be determined that its load matches the impedance of the deviation circuit source and does not exceed the source capacity. Consider the transfer loads when the system is capable of transfer (§ 27.1301).
(C) Malfunction indicator circuit loading. It should be determined that its load matches the impedance of the malfunction indicator source and does not exceed the source capacity. Consider the transfer loads when the system is capable of transfer (§ 27.1301).
(D) Synchro signal loading. When adding parallel loads to synchros, review the manufacturers' specifications to assure that the additional loads do not result in an overloaded synchro.
(iv) Interface. In many cases, different manufacturers design the mating units of a system. For example, a brand-X gyro may be designed for operation with a brand-X flight director, but later a modifier decides to operate a brand-Y autopilot with the brand-X gyro. This applies just as well to navigational (NAV) receivers, Area NAV (RNAV) units, course indicators, omni bearing selectors, tachometer indicators, transmitters, and many other equipment items. When this is the case, the applicant should provide data, in summarized form, describing those characteristics such as impedance, volts, etc., that are necessary to ensure a compatible and reliable system.
The data should also reference the source of the interface data (§ 27.1301).
(v) Flight Tests. An FAA/AUTHORITY engineering flight test is required during type certification or after modification that changes the established limitations, flight characteristics, or performance of a rotorcraft or any of its required systems or operating procedures. Appropriate flight test personnel should evaluate new installations of equipment in the cockpit or modifications that affect existing equipment in the cockpit, if it is necessary to evaluate operational aspects of the change. If the applicant opts to darken the windows, evaluate the cockpit arrangement, placards, markings, instrument visibility, and light reflections on the ground, where possible.
Conduct electromagnetic compatibility tunctional checks, windshield glare, and pilot workload evaluations in flight at the FAA/AUTHORITY flight test pilot's option.
(vi) Radio Master Switches. Some installations incorporate radio master switches to control special busses for the avionics systems. If providing this capability, evaluate it to ensure no introduction of failure modes that will result in excessive or even total loss of all required avionics. One switch that controls all required avionics is unacceptable for instrument flight rules (IFR) installations. The evaluation should include an assessment of the loss of the systems to be included on the radio master switches), and the subsequent effect on continued safe flight.
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AC 27-1B, Chg 7 2/4/2016
b. Test Procedures. Where the airworthiness or operating regulations require a system to perform its intended function, and not create a hazard to other required systems, accomplish sufficient testing to ensure satisfactory performance. When ground testing is not sufficient to evaluate a system's performance properly, accomplish flight testing. Acceptable flight test criteria for specific navigation and communication equipment are contained herein. If seeking IFR operations approval for the rotorcraft, satisfy the additional criteria of section AC 27 Appendix B of this AC.
(1) VHF Systems.
(i) General. Provide intelligible communications between the rotorcraft and ground facilities throughout the airspace within 80 nautical miles (NM) of an FAA/AUTHORITY ground facility from radio line of sight altitude to the maximum altitude for which the rotorcraft is certificated. Provide communication with the rotorcraft at or above line of sight altitude in right and left bank up to 10° and on all headings.
(ii) Electromagnetic Compatibility (EMC). With all systems operating in flight, verify by observation that no adverse effects are present in the flight systems.
Complete a qualitative evaluation of VHF radio navigation and communication equipment operation. Further guidance may be found in AC 43.13-2B, Chapter 2, paragraph 209.
(III) Antenna Measurement. If provided satisfactory antenna measurement data, reduce the following flight test to checks in right and left turns near the predicted bearings of worst performance. If antenna locations are symmetrical, conduct tests using only one turn direction.
(A) Long range reception. Starting at a distance of 80 NM from the ground facility antenna, perform a right or left 360° turn at a bank angle of at least 10°.
Communicate with the ground facility every 10° of turn to test the intelligibility of the signals received at the ground station and in the rotorcraft. For 80 NM, the minimum line of sight altitude is approximately 4,000 feet.
(B) Approach configuration. With the landing gear down and with the rotorcraft in the approach configuration (at a distance of 10 NM from the ground station and in an idle power descent toward the station), demonstrate intelligible communications between the rotorcraft and the ground facility.
(2) HF Systems.
(1) Demonstrate acceptable communications by contacting a ground facility at a distance of at least 80 NM. Single sideband equipment should also perform acceptably in the amplitude modulation mode of operation.
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(i) Demonstrate that precipitation static is not excessive when the aircraft is flying at cruise speed (in areas of high electrical activity, including clouds and rain if possible). Use the minimum number of installed dischargers.
(3) Very High Frequency Omnidirectional Range (VOR) Systems.
(i) Reduce these flight tests if adequate studies of antenna radiation pattern have shown the patterns to be without significant holes with the rotorcraft configurations used in flight (i.e., landing gear retracted en route and extended for approach). Make particular note to recognize that certain rotor RPM settings may cause modulation of the course deviation indication (rotor modulation). VOR performance should be checked for rotor modulation in both approach and en route operation while varying rotor RPM throughout its normal range.
(ii) The airborne VOR system should operate normally with warning flags out of view at all headings of the rotorcraft (in level flight) throughout the airspace within 80 NM of the VOR facility while flying above the radio line of sight altitude to within 90 to 100 percent of the maximum altitude for which the rotorcraft is certified.
(ilI) The indicated reciprocals accuracy determination should agree to within 2°. Conduct the tests over at least two known points on the ground to obtain data in each quadrant. Data should correlate with the ground calibration with no absolute error exceeding ‡6°. Fluctuation of the course deviation indication should not be excessive.
(A) Enroute Reception. Fly from a VOR facility along a radial to a range of 80 NM. The VOR warning flag should not come into view nor should the station identification signal deteriorate. The course width should be 20° (‡5° tolerance, 10° either side at the selected radial). If practical, perform en route segment on a doppler VOR station to verify the compatibility of the airborne unit. There have been large errors when incompatibility exists.
(B) Long range reception. Perform a 360° right and a 360° left turn at a bank angle of at least 10° at an altitude just above radio line of sight (see paragraph
b. (1) (ilI) (A) above for line of sight altitude) and at a distance of 80 NM from the VOR facility. Signal dropout should not occur as evidenced by the malfunction indicator appearance. Dropouts that are relieved by a reduction of bank angle at the same relative heading to the station are satisfactory. The VOR identification should be satisfactory during the left and right turns.
(C) Enroute station passage. Verify that the To-From indicator correctly changes as the rotorcraft passes through the cone of confusion above a VOR facility.
(4) Localizer Systems.
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AC 27-1B, Chg 7 2/4/2016
(i) Flight test requirements may be modified to allow for adequate antenna radiation pattern measurements as discussed under VOR systems, paragraph b. (3)(i) above.
(ii) The signal input to the receiver presented by the antenna system should be of sufficient strength to keep the malfunction indicator out of view when the rotorcraft is in the approach configuration and at least 10 NM from the station. This signal should be received for 360° of rotorcraft heading at all bank angles up to 10° left or right at all normal pitch altitudes, and at an altitude of approximately 2,000 feet.
(iii) The deviation indicator should properly direct the aircraft back to course when the rotorcraft is right or left of course.
(iv) The station identification signal should be of adequate strength and sufficiently free from interference to positive station identification, and voice signals should be intelligible with all electric equipment operating and pulse equipment transmitting.
(v) Localizer performance should be checked for rotor modulation in approach while varying rotor RPM throughout its normal range.
(A) Localizer intercept. In the approach configuration and a distance of at least 10 NM from the localizer facility, fly toward the localizer front course, inbound, at an angle of at least 50°. Perform this maneuver from both left and right of the localizer beam. No flags should appear during the time the deviation indicator moves from full deflection to on course. If the total antenna pattern are not been shown to be adequate by ground checks or by VOR flight evaluation, additional intercepts should be made.
(B) Localizer tracking. While flying the localizer inbound and not more than 5 miles before reaching the outer marker, change the heading of the rotorcraft to obtain full needle deflection. Then fly the rotorcraft to establish localizer on course operation. The localizer deviation indicators should direct the rotorcraft to the localizer on course. Perform this maneuver with both a left and a right needle deflection.
Continue tracking the localizer until over the transmitter. Conduct at least three acceptable front and back course flights to 200 feet or less above threshold.
(5) Glide Slope Systems.
(i) Flight Test. The signal input to the receiver should be of sufficient strength to keep the warning flags out of view at all distances to 10 NM from the facility.
Demonstrate this performance at all aircraft headings from 30° left to 30° right of the localizer course. The deviation indicator should properly direct the aircraft back to path when the aircraft is above or below path. Interference with the navigation operation should not occur with all rotorcraft equipment operating and all pulse equipment transmitting. There should be no interference with other equipment because of glide slope operation.
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(il) Glide Slope Intercept. While flying the localizer course inbound in level flight, intercept the glide slope below path at least 10 NM from the station. Observe the glide slope deviation indicator for proper crossover as the aircraft flies through the glide path. No flags should appear between the times the needle leaves the full-scale fly-up position and it reaches the full-scale fly-down position.
(ili) Glide Slope Tracking. While tracking the glide slope, maneuver the aircraft through normal pitch and roll attitudes. The glide slope deviation indicator should show proper operation with no flags. Conduct at least three acceptable approaches to 200 feet or less above threshold.
(iv) Interference. With all rotorcraft electrical equipment operating and all pulse equipment transmitting, determine that there is no interference with the glide slope operation (some interference from the VHF may be acceptable), and that the glide slope system does not interfere with other equipment.
(v) Glide slope performance should be checked for rotor modulation during the approach while varying rotor RPM throughout its normal range.
(6) Marker Beacon System.
(i) The marker beacon annunciator light should be illuminated for a period of time representing 2,000 to 3,000 feet distance when flying at an altitude of 1,000 feet as it passes over a marker beacon as follows:
Altitude = 1,000 feet (AGL) Ground Speed Light Time (Seconds) Knots 2,000 feet 3,000 feet 90 13 20 110 11 16 130 9 14 150 8 12
(il) The audio signal should be of adequate strength and sufficiently free from interference to provide positive identification.
(ill) Technical. Approach the markers at a ground speed of 130 knots and at an altitude of 1,000 feet above ground level. While passing over the outer and middle markers with the localizer deviation indicator centered, the annunciators should illuminate for 9 to 14 seconds. Check for acceptable intensity of the indicator lights in bright sunlight and at night. For slower rotorcraft, the interval should be proportionately longer.
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AC 27-1B, Chg 7 2/4/2016 Note: We recognize that the normal altitude at the middle marker is approximately 150 to 200 feet. Due to variations in both glide slope angle and position of the middle marker in relation to the runway, the on glide path marker width will vary considerably, which in turn will give a widely varying light time. Therefore, use the more clearly defined criteria at 1,000-feet altitude for quantitative testing of the middle marker function.
(7) Automatic Direction Finding Equipment (ADF).
(i) Range and Accuracy. The ADF system installed in the rotorcraft should provide operation with errors not exceeding 5° and the aural signal should be clearly readable up to the distance listed for any one of the following types of radio beacons:
(A) 50 NM from an homing (H) facility (transmitter power at 50-2,000 watts).
(B) 25 NM from an medium homing (MH) facility (transmitter power less than 50 watts).
(C) 15 NM from a compass locator (transmitter power less than 25 watts).
(II) Needle Reversal. The ADF indicator needle should make only one 180° reversal when the rotorcraft flies over a radio beacon. Make this test both with and without the landing gear extended.
(ili) Indicator Response. When switching stations with relative bearings differing by approximately 175°, the indicator should indicate the new bearing within t5° within 10 seconds.
(iv) Antenna Mutual Interaction. For dual installations, there should not be excessive coupling between the antennas.
(v) Technique.
(A) Range and accuracy. Tune in a number of radio beacons spaced throughout the 200 to 415 kHz range and located at distances near the maximum range for the beacon (see paragraph b.(7)(i), Range and Accuracy, above). The identification signals should be clear and the ADF should indicate the approximate direction to the stations. Beginning at a distance of at least 15 NM from a compass locator in the approach configuration, fly inbound on the localizer front course and make a normal instrument landing system (ILS) approach. Evaluate the aural identification signal for strength and clarity and the ADF for proper performance with the receiver in the ADF mode. All electrical equipment on the aircraft should be operating and all pulse equipment should be transmitting. Fly over a ground check point with relative bearings Page MG 1 -8