of its predictive validity, sensitivity, reliability, applicability to the particular cockpit configuration, and availability of a suitable reference for comparison.
(2) Analytical Approach.
One analytical approach defines workload as a percentage of the time available to perform tasks (Time Line Analysis). This process may be applied to an appropriate set of flight segments in which operationally important time constraints can be identified. This method is useful for evaluation of cockpit changes relating to overt pilot work such as control movements and data inputs. The generally accepted practice involves careful selection of the limited set of flight scenarios and time segments that represent the range of operational requirements (including the range of normal and non normal procedures.) Time line analysis yields useful data when tasks must be performed within operationally significant time constraints. The adequacy of this method is very much dependent on an accurate determination of the time available.
Absolute standards are not available for interpretation of obtained time required scores, but such records can be used to identify high or simultaneous workload demands for later testing in a simulator or aircraft, and comparisons can be made with overt workload demands in proven aircraft. However, the impact of cockpit changes on planning and decisionmaking is difficult to quantify by this method.
(i) The most frequently used basis for deciding that a new design is acceptable is a comparison of a new design with previous designs proven in operational service. By making specific evaluations using the acceptable human factors techniques, and comparing new designs to a known baseline, it is possible to proceed with confidence that the changes incorporated in the new designs accomplish the intended result. When the new cockpit is considered, certain components may be proposed as replacements for conventional items, and some degree of rearrangement may be contemplated. New avionics systems may need to be fitted into existing panels, and newly automated systems may replace current indicators and controls. As a result of this evolutionary characteristic of the cockpit design process, there is frequently a reference cockpit design, which is usually a conventional aircraft that has been through the test of operational usage. If the new design represents an evolution, improvement attempt, or other deviation from this reference cockpit, the potential exists to make direct comparisons. Service experience should be researched to assure that any existing problems are understood and not perpetuated.
(iii) If preliminary analysis by the certification team identify potential problem areas, these areas should receive more extensive evaluation and data collection in order to verify compliance with § 29.1523. These concerns should be adequately addressed in the manufacturer's demonstration plan when submitted to the FAAJAUTHORITY.
(iv) If the new design represents a significant change in level of automation or pilot duties, analytic comparison to a reference design may have Par 726 1109
lessened value. Without a firm data base on the time required to accomplish both normally required and contingency duties, more complete and realistic simulation and flight testing will be required.
(3) Testing.
(i) In the case of the minimum crew determination, the final decision is reserved until the rotorcraft has been flown by experienced flight test pilots trained and current in the aircraft. More assurance is derived from actual flight tests than from earlier simulator tests or other synthetic or computer model procedures.
(її) The test program should address the workload functions and factors listed below. For example, an evaluation of communications workload should include the basic workload required to properly operate the aircraft in the environment for which approval is sought. The goal is to evaluate workload with the proposed crew complement during realistic operating conditions, including representative air traffic and weather.
(A) Basic workload functions. The following basic workload functions are considered:
(1) Flight path control.
(2) Collision avoidance.
(3) Navigation.
(4) Communications.
(5) Operation and monitoring of aircraft engines and systems.
(6) Command decisions.
(B) Workload factors. The following workload factors are considered significant when analyzing and demonstrating workload for minimum flight crew determination:
(1) The accessibility, ease, and simplicity of operation of all necessary flight, power, and equipment controls, including emergency fuel shutoff valves, electrical controls, electronic controls, and engine controls.
(2) The accessibility and conspicuity of all necessary instruments and failure warning devices such as fire warning, electrical system malfunction, and other failure or caution indicators. The extent to which such instruments or devices direct the proper corrective action is also considered.
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(3) The number, urgency, and complexity of operating procedures with particular consideration given to the specific fuel management schedule imposed by center of gravity, structural or other considerations of an airworthiness nature, and to the ability of each engine to operate at all times from a single tank or source which is automatically replenished if fuel is also stored in other tanks.
(4) The degree and duration of concentrated mental and physical effort involved in normal operation and in diagnosing and coping with malfunctions and emergencies.
(2) The extent of required monitoring of the fuel, hydraulic, electrical, electronic, deicing, and other systems while en route.
(6) The actions requiring a crewmember to be unavailable at his assigned duty station, including: observation of systems, emergency operation of any control, and emergencies in any compartment.
(Z) The degree of automation provided in the aircraft systems to afford (after failures or malfunctions) automatic crossover or isolation of difficulties to minimize the need for any flight crew action to guard against loss of hydraulic or electric power to flight controls or to other essential systems.
(8) The communications and navigation workload.
(9) The possibility of increased workload associated with any emergency that may lead to other emergencies.
727. § 29.1525 (Amendment 29-24) KINDS OF OPERATION.
This rule states that the kinds of operation to which the rotorcraft is limited are established by demonstrated compliance with applicable certification requirements (primarily flight) and the equipment requirements established for that kind of operation.
The basic flight characteristics requirements of Part 29 are suitable for day VFR approval. Additional night considerations appear in § 29.141(c) and in the operating rules. FR requirements are addressed in § 29.141(c) and Appendix B to Part 29.
Additional IFR equipment requirements are contained in the operating rules. Icing certification criteria are contained in Paragraph 386 of this AC. External load requirements for certification may be found in §$ 29.25(c) and 29.865(c) in addition to Part 133. Related § 29.1525(d) further requires that the approved kinds of operation must be listed in the operating limitations section of the Rotorcraft Flight Manual. The equipment that is necessary for a specific kind of operation other than basic day VFR operation should also be listed in the limitations section of the RFM.
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728. § 29.1527 (Amendment 29-15) MAXIMUM OPERATING ALTITUDE.
a. Explanation. This rule requires that the maximum altitude for operation of the rotorcraft must be established as an operating limitation. The rule is intended to establish en route altitude as an operating limit. The requirements for maximum takeoff and landing altitude are contained in other portions of the rule. (See discussion in Paragraph 81a(2) (il) of this advisory circular.) The en route limit may be established by any of the preceding subparts of the rule involving flight, structural, powerplant, equipment or related functional requirements of those subparts. Maximum operating altitude is ordinarily specified initially by the manufacturer and substantiated throughout the type certification program by each engineering discipline. Maximum operating altitude must be established in terms of pressure altitude unless the pilot is provided with some equally functional means of observing specified altitude limits (e.g., a density altitude indicator if maximum altitude is specified in terms of density altitude). A related requirement in § 29.1583 specifies that maximum operating altitude must be established as an operating limitation in the Rotorcraft Flight Manual and further that any limiting factors must be identified and explained.
b. Procedures. Each FAA/AUTHORITY engineering discipline must assure that data and testing are adequate to properly substantiate and qualify all critical components to the maximum operating altitude of the rotorcraft. The design or maximum substantiated altitude should be specified in the Type Inspection Authorization. The flight test program must include at least one test flight to the maximum approved altitude and this flight must include functional testing of all critical aircraft components. Due to specific requirements in § 29.21(b), no extrapolation of these results is allowed.
729. § 29.1529 (Amendment 29-20) INSTRUCTIONS FOR CONTINUED AIRWORTHINESS (MAINTENANCE MANUAL).
a. Explanation. The FAA/AUTHORITY has long recognized the necessity to have a maintenance manual for rotorcraft due to the unique and generally complicated and critical design features.
(1) Airworthiness Limitations Section.
Amendment 29-4, October 1968, established the requirement for a separate and specific airworthiness limitations section. Section 43.15 was already in place. New § 43.16 was added to the maintenance rules, and § 91.163(c) was added to the operating rules to require compliance with this section of the maintenance manual.
(її) Amendment 29-20, October 1980, revised the rule and added Appendix A containing requirements for preparation of instructions for continued airworthiness, including the airworthiness limitations section. Instructions for continued 1112 Par 728
airworthiness replaced "rotorcraft maintenance manual" in the standard. The maintenance rules, §§ 43.15 and 43.16, and § 91.163(c) of the operating rules also refer to, or require, compliance with certain parts of the instructions for continued airworthiness. The airworthiness limitations were intended to define the limits of the type certification approval of the fatigue characteristics of "critical flight structure."
(2) Rotorcraft type designs are unique in comparison to airplane designs in that transmissions and rotors have critical components that may be adversely affected by operating conditions and time in service. The FAA/AUTHORITY-approved airworthiness limitations section may include such items as gear sets, bearings, etc., of the rotorcraft type design if a finite life was established during the type certification program and if the FAA/AUTHORITY determined that mandatory inspections and/or replacement of the component (part) was necessary to maintain airworthiness of the rotorcraft. For example, a drive spline, gear, or bearing was serviceable after concluding the ground endurance test and/or FAA/AUTHORITY flight test program.
However, an FAA/AUTHORITY-mandated inspection or replacement of the component was considered essential for airworthiness of the rotorcraft type design and necessary for type certification. Time between overhaul (TBO) of components is not part of the airworthiness limitations. If an inspection or replacement of a part in an assembly is required, the inspection interval or replacement time and the part number should be included in the limitations. The inspection interval or replacement time may or may not coincide with the recommended overhaul interval of the assembly. (See the comments for Proposal 8-25, § XX.4 in the preamble of Amendment 29-20 (45 FR 60154, September 11, 1980). Note that parts considered unserviceable at the conclusion of the ground endurance test of § 29.923 are not acceptable for type certification.
(3) Certain components must be identified by part number (or equivalent) and serial number (or equivalent). Section 29.1529(a)(1) and (2) of Amendment 29-4 and § 45.14 of Amendment 45-12 list the requirements. The part number of parts and/or components requiring inspections and/or replacement as a result of § 29.571 or other standards must be listed in the airworthiness limitations section of the manual or another separate, segregated section of the manual appropriate to the rules.
(4) Control rigging procedures are included in the manuals. Since rotorcraft are generally difficult to rig properly, it is important that these procedures be correct and complete.
b. Procedures.
(1) General.
The rule of Amendment 29-4 and its predecessor stated that the maintenance manual must contain all information that the applicant considers essential for proper maintenance. Amendment 29-4 also added the requirement for an airworthiness limitations section. Amendment 29-20 revised § 29.1529 and added Par 729 1113
Appendix A that now contains the requirements for content and preparation of the manual. The airworthiness limitations section of the manual, and any revisions thereto, must be FAA/AUTHORITY approved. The "continued airworthiness" sections which contain the manufacturer's recommendations for continued airworthiness are not FAA/AUTHORITY approved.
(¡¡) The airworthiness limitations section contains information derived primarily but not solely from the data approved under § 29.571. Approval of this section of the manual must be completed before type certification. See Part 29, Appendix A, Paragraph A29.4 of Amendment 29-20. (For further information, see the comments for Proposal 8-25, § XX.4 in the preamble of Amendment 29-20 (45 FR 60154, September 11, 1980)).
(III) Part 29, Appendix A, Paragraphs A29.3(a) and (b) pertain to the content of the instructions for continued airworthiness. For example, scheduling, overhauls (including recommended overhaul periods or TBO), inspections, and servicing information are included in this section of the manual.
(2) Identifying and Serializing Fatigue Critical Components.
(i) Part numbers and serial numbers must be applied to fatigue life limited components as noted in $$ 45.14 and 29.1529(a)(1) and (2) of Amendment 29-4. Electric arc marking methods should not be used due to possible internal arcing, pitting of surfaces, and changes in physical or chemical characteristics due to the local high temperature at the arcs.
(її) Vibrating pencils, name plates, or permanent inks may be used.
However, serial numbers should be applied on each part such that material is upset or displaced on the part, thereby attaining a more permanent number. This is not a requirement however. When material is upset or displaced, the least critical or lowest stressed area should be used.
(iii) For small parts, the rule (§ 45.14) allows markings that are equivalent to part and serial numbers. Markings or symbols may be used to enable the identification of a part as one for which a replacement time, inspection interval, or related procedure is specified in the airworthiness limitations section. The FAA/AUTHORITY-stated identification of such small parts is clearly essential for safety and may not be relieved. With adoption of Amendment 29-20, the marking requirements that were contained in § 29.1529 are now contained in § 45.14, Amendment 45-12.
(3) The FAAJAUTHORITY inspector should witness the rigging of the controls of a test rotorcraft. This is imperative for a new rotorcraft design to ensure the practicality and feasibility of the procedures stated in the design data and/or the maintenance manual. The type design data information should be used, and the 1114 Par 729
FAAJAUTHORITY should ensure the manual includes the proper information. Rigging procedures are not included in the airworthiness limitations section.
(4) As a recommendation, a draft copy of the manual should be available to the FAA/AUTHORITY for use during the F&R program if such a program is conducted under § 21.35(b). The manual must be completed and furnished with each aircraft receiving an airworthiness certificate, § 21.50(a) and (b).
For rotorcraft certified to § 29.1529(a) (2) of Amendment 29-4, changes to the airworthiness limitations shall be furnished on request. See § 21.50(a).
(ii) For rotorcraft certified to § 29.1529 of Amendment 29-20, changes to the manual shall be made available to those that need the manual. See § 21.50(b).
(5) Service experience may dictate additional and subsequent (to type certification) changes to the airworthiness limitations section. AD's may be used to revise the limitations. (The relationship between AD's and the process of changing these limitations is covered in the preamble of Amendment 29-4 (33 FR 14104;
September 18, 1968.) Whenever the revised limitations are made restrictive for aircraft in service, the Administrative Procedures Act requires "notice and public procedure" to persons that may be affected and to satisfy the requirement for notification of the changes and identification of the correct issue of the airworthiness limitations, if appropriate. This procedure is also used for restrictive or reduced operation limitations in the RFM.
(6) FAA Order 8620.2, November 2, 1978, Applicability and Enforcement of Manufacturers Data, may be reviewed for further information. This does not reflect the rule changes made in October 1980 but applies to prior standards.
729A. § 29.1529 (Amendment 29-26) INSTRUCTIONS FOR CONTINUED AIRWORTHINESS (MAINTENANCE MANUAL).
a. Explanation. Amendment 91-21, 54 FR 41211, October 5, 1989, recodified certain paragraphs in FAR Part 91. This revision corrects a reference from FAR § 91.163 to FAR § 91.403.
b. Procedures. Correct the references in Paragraph 729a(1) from §§ 43.15,
43.16, and 91.163(c) to §§ 43.15, 43.16, and 91.403 of the operating rules.
730.-739. RESERVED.
Par 729 1115 (thru 1125)
SECTION 41. MARKINGS AND PLACARDS
740. § 29.1541 GENERAL. (SEE PARAGRAPH 781).
741. § 29.1543 INSTRUMENT MARKINGS: GENERAL. (ŞEE PARAGRAPH 781).
742. § 29.1545 (Amendment 29-17) AIRSPEED INDICATOR. (SEE PARAGRAPH 781)
743. § 29.1547 MAGNETIC DIRECTION INDICATOR.
a. Explanation. This regulation identifies the requirement for a calibration placard for the magnetic direction indicator and where it should be located.
b. Procedures. One means of accomplishing the requirements of this regulation is commonly known as swinging the compass. A surveyed compass rose is laid out on an appropriate surface. The compass rose location should be free from the influence of steel structures, underground pipes and cables, reinforced concrete, and other aircraft.
The aircraft should be in an attitude which permits an accurate result. Normally the engines are in operation; however, if the rotorcraft is equipped with an auxiliary power unit which can supply all required electrical power, this can be used in lieu of engine driven generators. Turn the aircraft on successive headings through 360°. It is recommended that the increments be every 30°; however, the increments should not exceed 45°. Prepare a placard to show the correction to be applied at each of the selected headings. When significant errors are introduced by operation of electrical/electronics equipment or systems, the placard should also be marked at each calibration heading showing the correction to be applied when such equipment or systems are turned on or energized. The placard resulting from this calibration should be installed on or near the magnetic direction indicator.
744. § 29.1549 (Amendment 29-34) POWERPLANT INSTRUMENTS. (SEE PARAGRAPH 781).
745. § 29.1551 OIL QUANTITY INDICATORS.
a. Background. This section states that each oil quantity indicator must be marked with enough increments to indicate oil quantity readily and accurately.
b. Procedures. There are several different ways in which the oil quantity indicator may be presented. Some of the ones more prevalent in the industry are:
(1) Oil quantity indicator. (Generally used when large amounts of reserve oil are required.)
(2) Oil quantity dip stick. (Most common method of measuring engine oil.)
1126 Par 740
(3) Oil quantity sight indicator. (Generally used for measuring transmission and gearbox oil quantities.)
c. No matter what method of oil quantity indicator is used, the indicator should be marked so that the oil quantity can be accurately determined. This can range from increments marked in gallons, such as oil quantity indicators for large amounts of oil, to oil quantity indicators marked in quarts with full and add marks, such as engine dip sticks. Sight indicators with full and add marks have been used successfully for gearboxes. Sight indicators normally do not reflect quantities. These are some of the methods currently in use to indicate the oil quantity. In all cases, those methods identified above have proved to be an acceptable method of showing compliance with § 29.1551.
746. § 29.1553 FUEL QUANTITY INDICATOR.
a. Explanation. This section describes the markings necessary to identify the portion of unusable fuel that cannot be used in level flight. Unusable fuel may be present in a design due to the relative configuration of the fuel tank to the fuel tank outlet (e.g., sumps, unusual elevations and/or configurations dictated by aircraft contours, etc.). If the unusable fuel supply for any tank is less than or equal to 1 gallon or is less than or equal to 5 percent of the tank capacity, whichever is greater, this section does not apply.
b. Procedures. For each fuel tank which has an unusable fuel capacity exceeding 1 gallon or 5 percent of the tank capacity, whichever is greater, the following should be accomplished:
(1) Calibration computations, measurements, and/or tests should determine the zero (empty) position on the fuel quantity indicator (reference § 29.1337).
(2) The lowest reading obtainable in level flight must be determined by computation, measurement, and/or testing.
(3) Once the instrument readings defined by Paragraphs b(1) and (2) above have been determined, a red arc should be placed between the readings on the fuel quantity indicator.
(4) Appropriate notations should be made in the flight manual to define the intent of the red arc to the flightcrew (reference § 29.1585(e)).
747. § 29.1555 (Amendment 29-24) CONTROL MARKINGS.
a. Explanation. Section 29.1301(b) requires that all installed equipment be labeled to identify its function and operation. This section provides more detailed Par 745 1127
requirements for control markings. Specific criteria are given for powerplant fuel controls, fuel quantity markings, and landing gear controls. The requirement to color emergency controls red is in this section.
b. Procedures.
(1) Section 29.1555(a) requires that each cockpit control, other than flight controls whose function is not obvious, must be appropriately labeled. The primary flight controls are the cyclic, collective, and the directional control (tail rotor) pedals. For the control to be appropriately labeled, the rule requires that there should be an obvious and clear demarcation of the function and operation of the control. When performing the evaluation to determine the adequacy of markings, it should be remembered that only those controls which are quite traditional should be judged to be obvious in their operation. An example of this has been the navigation/communication control heads.
The more traditional control units had concentric knobs of decreasing size for the selection of frequency. Because this system was so common for such a period of time, the finding was generally made that the function of this control was obvious and thus did not require a specific marking. However, as more current technology digital electronic controls were used, the frequency selectors were judged not to be obvious in their operation, and their function and operation were required to be labeled.
(2) Review design data and available hardware to ensure the powerplant fuel controls are clearly and permanently marked such that:
Selector valve control clearly shows each position for each tank and each crossfeed configuration.
Tank selection sequences required for safe operation are clearly and permanently marked on or adjacent to the required selector.
(ili) Each control valve is clearly marked to show the position of the controls for each engine on multiengine rotorcraft.
(3) Review design data and available hardware to ensure that usable fuel capacity is clearly marked as follows:
If the fuel system has no selector controls, usable fuel capacity must be shown on the fuel quantity indicator (reference Paragraph 746).
(ii) If the system has selector controls, the usable fuel capacity at each selector position must be clearly shown near the selector position.
(4) Markings of essential visual position indicators must be obvious and within view of required crewmembers. Landing gear markings normally include indications for down, intermediate/unsafe, and up. Accepted symbology has included arrows for 1128 Par 747
up/down indications, crosshatching for intermediate/unsafe, various combinations of colored lights, and combinations of all of the above. Cockpit presentation is further discussed in Paragraph 301. Emergency controls which should be marked in red include those used for firewall/emergency fuel shutoff, landing gear blowdown/emergency release, fire extinguishers, float activation, cargo hook release and fuel dump. The method of operation of emergency controls must be clearly marked. In the case of switches and buttons, the method of operation is often inherently obvious without dedicated labeling.
(5) The two most obvious means of displaying landing gear operating speed are use of a placard or an appropriate mark in the airspeed indicator.
748. § 29.1557 (Amendment 29-26) MISCELLANEOUS MARKINGS AND PLACARDS.
a. Explanation.
(1) This section specifies the markings and placards associated with baggage, cargo, ballast, seats, fuel, oil, and emergency exits.
(2) The data contained in these markings and placards must conform to the approved type design of the rotorcraft.
b. Procedure
(1) The placard for baggage and cargo compartment limitations should clearly state all limitations which apply to that compartment. The limitations may apply to what is carried, the dimensions, exact location, and maximum weight allowed. The placard should be located in a place where it cannot be obstructed and is clearly visible before or after opening the compartment. For ballast, the placard should state the type of ballast permitted (lead plate, shot bags, etc.), the exact placement, if applicable, and the maximum allowable weight. If there are other limitations which are applicable to these compartments, they should be clearly stated.
(2) Seats in rotorcraft are designed to meet vertical descent loads which have been established to insure a certain level of occupant survivability in the event of a hard landing or crash. To meet these load requirements, 170 pounds was established as the minimum occupant design weight. If the seat was designed and certified to an occupant weight lower than 170 pounds, the seat must carry a placard in a conspicuous place, which limits the weight of the seat occupant to the certified weight.
(3) The fuel and oil filler opening markings are self-explanatory.
Par 747 1129
(4) Emergency exit placards must be so distinctive and clear that they are easily identified and understood under extreme and intense circumstances by individuals who have little or no familiarity with aircraft escape procedures.
749. § 29.1559 (Amendment 29-24) LIMITATIONS PLACARD.
a. Explanation.
(1) The content and location requirements on the placard are specified in the standard. The content and information in the placard has changed significantly as a result of associated and complementary changes in the airworthiness rules and the maintenance and operating rules.
(2) By adoption of FAR Part 29 in 1965, the standard (and its predecessor CAR Part 7) required compliance with the operating limitations in the approved Rotorcraft Flight Manual.
(3) With the adoption of an Airworthiness Limitations Section for the maintenance manual as stated in § 29.1529 of Amendment 29-4, the content of the placard was changed significantly to require compliance with the requirements in that section.
(4) Amendment 29-20, issued in 1980, adopted standards requiring "Instructions for Continued Airworthiness" (maintenance manual). This manual may include an Airworthiness Limitations section which is segregated and an approved part of the manual. The maintenance and operating rules, §§ 43.16, 91.163(c), and other operating rules require compliance with the Airworthiness Limitations Section. Other airworthiness standards were adopted for airplanes, engines, and propellers to similarly require Instructions for Continued Airworthiness and an Airworthiness Limitations Section. See Paragraph 729 of this AC for further information. The limitations placard standard was not changed by this amendment.
(5) Amendment 29-24 adopted a significant change for the placard. The placard must be in clear view of the pilot and must provide a convenient cockpit presentation of the approved types of operation for each aircraft. Other operating and maintenance rules referenced in the previous paragraph provided the basis for much of the change in the placard content.
b. Procedures.
(1) A placard (or durable decal) must be legible to the pilot and located in clear view of the pilot. If two pilots are required, a single placard may satisty the standard.
This aspect will be evaluated by a test pilot. The type inspection report (TIR) should contain a compliance check entry.
1130 Par 748