Subpart C-Maintenance, Preventive Maintenance, and Alterations 1

§ 91.161 Applicability.

(a) This subpart prescribes rules governing the maintenance, preventive maintenance, and alteration of U.S. registered civil aircraft operating within or without the United States.

(b) Sections 91.165, 91.169, 91.170, 91.171, and 91.173 of this subpart do not apply to an aircraft maintained in accordance with a continuous airworthiness program under Part 121 or 127 of this chapter.

[Amdt. 91-15, 30 F.R. 3638, Mar. 19, 1965, as amended by Amdt. 91-20, 30 F.R. 8262, June 29, 1965; Amdt. 91–29, 31 F.R. 8355, June 15, 1966]

(a) The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition, including compliance with Part 39 of this chapter.

(b) No person may perform maintenance, preventive maintenance, or alterations on an aircraft other than as prescribed in this subpart and other applicable regulations, including Part 43 of this chapter.

X [Amdt. 91-19, 30 F.R. 8033, June 23, 1965, as amended by Amdt. 91-29, 31 F.R. 8355, June 15, 1966]

§ 91.165 Maintenance required.

Each owner or operator of an aircraft I shall have that aircraft inspected as prescribed in §§ 91.169 and 91.170 of this part and shall, between required inspections, have defects repaired as prescribed in Part 43 of this chapter. In addition, he shall ensure that maintenance personnel make appropriate entries in the aircraft and maintenance records indicating the aircraft has been released to service.

[Doc. No. 1580, Amdt. 1-1, 28, F.R. 6704, June 29, 1963, as amended by Amdt. 91-40, 32 F.R. 7587, May 24, 1967]

§ 91.167 Carrying persons other than crewmembers after repairs or alterations.

(a) No person may carry any person (other than crewmembers) in an aircraft that has been repaired or altered in a manner that may have appreciably changed its flight characteristics, or substantially affected its operation in flight,

130 F.R. 8033, June 23, 1965.

until it has been approved for return to service in accordance with Part 43 and an appropriately rated pilot, with at least a private pilot's certificate, flies the aircraft, makes an operational check of the repaired or altered part and logs the flight in the aircraft records.

(b) Paragraph (a) of this section does not require that the aircraft be flown if ground tests or inspections, or both, show conclusively that the repair or alteration has not appreciably changed the flight characteristics, or substantially affected the flight operation of the aircraft.

(49 U.S.C. 1354) [Amdt. 91-21, 30 F.R. 8473, July 2, 1965]

(a) Except as provided in paragraph (c) of this section, no person may operate an aircraft unless, within the preceding 12 calendar months, it has had

(1) An annual inspection in accordance with Part 43 of this chapter and has been approved for return to service by a person authorized by § 43.7 of this chapter; or

(2) An inspection for the issue of an airworthiness certificate.

No inspection performed under paragraph (b) of this section may be substituted for any inspection required by this paragraph unless it is performed by a person authorized to perform annual inspections, and is entered as an "annual" inspection in the required maintenance records.

(b) Except as provided in paragraph (c) of this section, no person may operate an aircraft carrying any person (other than a crewmember) for hire or to give flight instruction for hire unless, within the preceding 100 hours of time in service, it has been inspected in accordance with Part 43 of this chapter and approved for return to service by a person authorized by § 43.7. The 100-hour limitation may be exceeded by not more than 10 hours if necessary to reach a place at which the inspection can be done. The excess time, however, is included in computing the next 100 hours of time in service.

(c) Paragraphs (a) and (b) of this section do not apply to

(1) Any aircraft for which its registered owner or operator complies with the progressive inspection requirements

of § 91.171 and Part 43 of this chapter;

or

(2) An aircraft that carries a special flight permit or a current experimental or provisional certificate.

[Doc. No. 1580, Amdt. 1-1, 28 F.R. 6704, June 29, 1963, as amended by Amdt. 91-26, 31 F.R. 3337, Mar. 3, 1966; Amdt. 91-30, 31 F.R. 9211, July 6, 1966] § 91.170 spections.

Altimeter system tests and in

(a) No person may operate an airplane in controlled airspace under IFR unless, within the preceding 24 calendar months, each static pressure system and each altimeter instrument has been tested and inspected and found to comply with Appendix E of Part 43 of this chapter. The static pressure system and altimeter instrument tests and inspections may be conducted by

(1) The manufacturer of the airplane on which the tests and inspections are to be performed;

(2) A certificated repair station properly equipped to perform these functions and holding

(i) An instrument rating, Class I; (ii) A limited instrument rating appropriate to the make and model altimeter to be tested;

(iii) A limited rating appropriate to the test to be performed;

(iv) An airframe rating appropriate to the airplane to be tested; or

(v) A limited rating for a manufacturer issued for the altimeter in accordance with § 145.101(b) (4) of this chapter; or

(3) A certificated mechanic with an airframe rating (static pressure system tests and inspections only).

(b) The first test and inspection required by this section for airplanes, under annual inspection is not required to be made until the first annual inspection after July 31, 1967.

(c) No person may operate an airplane in controlled airspace under IFR at an altitude above the maximum altitude to which an altimeter of that airplane has been tested.

[Amdt. 91-40, 32 F.R. 7587, May 24, 1967] § 91.171 Progressive inspection.

(a) Each registered owner or operator of an aircraft desiring to use the progressive inspection must submit a written request to the Flight Standards District Office having jurisdiction over the

area in which the applicant is located, and shall provide

(1) A certificated mechanic holding an inspection authorization, a certificated airframe repair station, or the manufacturer of the aircraft, to supervise or conduct the progressive inspection;

(2) A current inspection procedures manual available and readily understandable to pilot and maintenance personnel containing, in detail—

(i) An explanation of the progressive inspection, including the continuity of inspection responsibility, the making of reports, and the keeping of records and technical reference material;

(ii) An inspection schedule, specifying the intervals in hours or days when routine and detailed inspections will be performed and including instructions for exceeding an inspection interval by not more than 10 hours while en route and for changing an inspection interval because of service experience;

(iii) Sample routine and detailed inspection forms and instructions for their use; and

(iv) Sample reports and records, and instructions for their use;

(3) Enough housing and equipment for necessary disassembly and proper inspection of the aircraft; and

(4) Appropriate current technical information for the aircraft.

(b) The frequency and detail of the progressive inspection shall provide for the complete inspection of the aircraft within each 12 calendar months and be consistent with the manufacturer's recommendations, field service experience, and the kind of operation in which the aircraft is engaged. The progressive inspection schedule must insure that the aircraft at all times will be airworthy and will conform to all applicable FAA aircraft specifications, type certificate data sheets, airworthiness directives, and other approved data.

(c) If the progressive inspection is discontinued, the owner or operator shall immediately notify the local General Aviation District Office, in writing, of the discontinuance. After that discontinuance, the first annual inspection under § 91.169 (a) is due within 12 calendar months after the last complete inspection of the aircraft under the progressive inspection. The 100-hour inspection under § 91.169 (b) is due within 100 hours

after that complete inspection. A complete inspection of the aircraft, for the purpose of determining when the annual and 100-hour inspections are due, will require a detailed inspection of the aircraft and all its components in accordance with the progressive inspection. A routine inspection of the aircraft and a detailed inspection of several components is not considered to be a complete inspection.

[Doc. No. 1580, Amdt. 1-1, 28 F.R. 6704, June 29, 1963, as amended by Amdt. 91-3, 29 F.R. 5451, Apr. 23, 1964]

§ 91.173 Maintenance records.

(a) Each registered owner or operator of an aircraft shall keep a separate, current, and permanent maintenance record for the aircraft and each engine and shall identify each record as to make, model, serial number, and, if applicable, registration number of the aircraft or engine concerned.

(b) Each registered owner or operator shall use a record of sufficient size and shall include in it the following information:

(1) The kind and extent of maintenance and alteration, and the time in service and date when the work is done. However, major repairs or major alterations may be logged by making reference to the FAA Form ACA-337 by date, or to the work order (by number) and the approving agency.

(2) A chronological listing of compliance with mandatory service bulletins, airworthiness directives, and the method of compliance.

(3) The current empty weight, empty center of gravity, and useful load.

(4) The addition or removal of optional equipment.

(5) The addition or removal of required equipment in exchange for optional equipment.

(6) The total time in service and history of each engine overhauled, repaired, or reassembled to standards other than those for rebuilt engines as defined in § 91.175.

(7) The total time in service of the aircraft.

(c) Each registered owner or operator shall

(1) Present the maintenance record for required entries each time inspection

or maintenance is done on the aircraft or engine;

(2) Upon disposing of the aircraft or engine, give the maintenance record to the new registered owner or operator; and

(3) Make the maintenance record available for inspection by the Administrator or any authorized representative of the National Transportation Safety Board.

(Secs. 3, 6, 9, 80 Stat. 931, 49 U.S.C. 1652, 1655, 1657) [Doc. No. 1580, Amdt. 1-1, 28 F.R. 6704, June 29, 1963, as amended by Doc. No. 8084, 32 F.R. 5769, Apr. 11, 1967]

§ 91.175 Rebuilt engine maintenance records.

(a) The owner or operator may use a new maintenance record, without previous operating history, for an aircraft engine rebuilt by the manufacturer or by an agency approved by the manufacturer.

(b) Each manufacturer or agency that grants zero time to an engine rebuilt by it shall enter, in the new record

(1) A signed statement of the date the engine was rebuilt;

(2) Each change made as required by Airworthiness Directives; and

(3) Each change made in compliance with manufacturer's service bulletins, if the entry is specifically requested in that bulletin.

(c) For the purposes of this section, a rebuilt engine is a used engine that has been completely disassembled, inspected, repaired as necessary, reassembled, tested, and approved in the same manner and to the same tolerances and limits as a new engine with either new or used parts. However, all parts used in it must conform to the production drawing tolerances and limits for new parts or be of approved oversize or undersized dimensions for a new engine.

APPENDIX A

CATEGORY II OPERATIONS: MANUAL, INSTRUMENTS, EQUIPMENT AND MAINTENANCE

1. Category II Manual—(a) Application for approval. An applicant for approval of a Category II manual or an amendment to an approved Category II manual must submit the proposed manual or amendment to the General Aviation District Office having jurisdiction of the area in which the applicant is located. If the application requests an

evaluation program, it must include the following:

(1) The location of the airplane and the place where the demonstrations are to be conducted; and

(2) The date the demonstrations are to commence (at least 10 days after filing the application).

(b) Contents. Each Category II manual must contain

(1) the registration number, make, and model of the airplane to which it applies;

(2) A maintenance program as specified in section 4 of this Appendix; and

(3) The procedures and instructions related to recognition of decision height, use of runway visual range information, approach monitoring, the decision region (the region between the middle marker and the decision height), the maximum permissible deviations of the basic ILS indicator within the decision region, a missed approach, use of airborne low approach equipment, minimum altitude for the use of the autopilot, instrument and equipment failure warning systems, instrument failure, and other procedures, instructions, and limitations that may be found necessary by the Administrator.

2. Required instruments and equipment. The instruments and equipment listed in this section must be installed in each airplane operated in a Category II operation. This section does not require duplication of instruments and equipment required by § 91.33 or any other provisions of this chapter.

(a) Group I. (1) Two localizer and glide slope receiving systems. However, a single localizer antenna and a single glide slope antenna may be used.

(2) A communications system that does not affect the operation of at least one of the ILS systems.

(3) A marker beacon receiver that provides distinctive aural and visual indications of the outer and the middle marker.

(4) Two gyroscopic pitch and bank indicating systems.

(5) Two gyroscopic direction indicating systems.

(6) Two airspeed indicators.

(7) Two sensitive altimeters adjustable for barometric pressure, each having a placarded correction for altimeter scale error and for the wheel height of the airplane.

(8) Two vertical speed indicators.

(9) A flight control guidance system that consists of either an automatic approach coupler or a flight director system with dual displays, or both. A single axis flight director system giving computed roll information is acceptable if basic guide slope information is displayed on each of the dual displays.

(10) For Category II operations with decision heights below 150 feet, either a marker beacon receiver providing aural and visual indications of the inner marker or a radio altimeter.

(b) Group II. (1) Warning systems for immediate detection by the pilot of system faults in items (1), (4), (5), and (9) of Group I and, if installed, for use in Category II operations, the radio altimeter and auto throttle system.

(2) Dual controls.

(3) An externally vented static pressure system with an alternate static pressure

source.

(4) A windshield wiper or equivalent means of providing adequate cockpit visibility for a safe visual transition by either pilot to touch down and roll out.

(5) A heat source for each airspeed system pitot tube installed or an equivalent means of preventing malfunctioning due to icing of the pitot system.

3. Instruments and equipment approval(a) General. The instruments and equipment required by section 2 of this Appendix must be approved as provided in this section before being used in Category II operations. Before presenting an airplane for approval of the instruments and equipment, it must be shown that, since the beginning of the 12th calendar month before the date of submission

(1) The ILS localizer and glide slope equipment were bench checked according to the manufacturer's instructions and found to meet those standards specified in RTCA Paper 23-63/DO-117, dated March 14, 1963, "Standard Adjustment Criteria for Airborne Localizer and Glide Slope Receivers," which may be obtained from the RTCA Secretariat, 2000 K Street NW., Washington, D.C. 20006, at cost of 50 cents per copy, payment in cash or by check or money order payable to the Radio Technical Commission for Aeronautics;

(2) The altimeters and the static pressure systems were tested and inspected in accordance with Appendix E to Part 43 of this chapter; and

(3) All other instruments and items of equipment specified in section 2(a) of this Appendix that are listed in the proposed maintenance program were bench checked and found to meet the manufacturer's specifications.

(b) Flight control guidance system. All components of the flight control guidance system must be approved as installed by the evaluation program specified in paragraph (e) of this section if they have not been approved for Category II operations under applicable type or supplemental type certification procedures. In addition, subsequent changes to make, model or design of these components must be approved under this paragraph. Related systems or devices such as the auto throttle and computed missed approach guidance system must be approved in the same manner if they are to be used for Category II operations.

(c) Radio altimeter. A radio altimeter must meet the performance criteria of this

paragraph for original approval and after each subsequent alteration.

(1) It must display to the flight crew clearly and positively the wheel height of the main landing gear above the terrain.

(2) It must display wheel height above the terrain to an accuracy of plus or minus 5 feet or 5 percent, whichever is greater, under the following conditions:

(1) Pitch angles of zero to plus or minus 5 degrees about the mean approach attitude. (ii) Roll angles of zero to 20 degrees in either direction.

(iii) Forward velocities from minimum approach speed up to 200 knots.

(iv) Sink rates from zero to 15 feet per second at altitudes from 100 to 200 feet.

(3) Over level ground, it must track the actual altitude of the airplane without significant lag or oscillation.

(4) With the airplane at an altitude of 200 feet or less, any abrupt change in terrain representing no more than 10 percent of the airplane's altitude must not cause the altimeter to unlock, and indicator response to such changes must not exceed 0.1 second, and in addition, if the system unlocks for greater changes, it must reacquire the signal in less than 1 second.

(5) Systems that contain a push-to-test feature must test the entire system (with or without an antenna) at a simulated altitude of less than 500 feet.

(6) The system must provide to the flight crew a positive failure warning display any time there is a loss of power or an absence of ground return signals within the designed range of operating altitudes.

(d) Other instruments and equipment. All other instruments and items of equipment required by section 2 of this Appendix must be capable of performing as necessary for Category II operations. Approval is also required after each subsequent alteration to these instruments and items of equipment.

(e) Evaluation program—(1) Application. Approval by evaluation is requested as a part of the application for approval of the Category II manual.

(2) Demonstrations. Unless otherwise authorized by the Administrator, the evaluation program for each airplane requires the demonstrations specified in this subparagraph. At least 50 ILS approaches must be flown with at least five approaches on each of three different ILS facilities and no more than one-half of the total approaches on any one ILS facility. All approaches shall be flown under simulated instrument conditions to a 100-foot decision height and 90 percent of the total approaches made must be successful. A successful approach is one in which

(i) At the 100-foot decision height, the indicated airspeed and heading are satisfactory for a normal flare and landing (speed must be plus or minus 5 knots of programed airspeed but may not be less than

computed threshold speed, if auto throttles are used);

(ii) The airplane, at the 100-foot decision height, is positioned so that the cockpit is within, and tracking so as to remain within, the lateral confines of the runway extended;

(iii) Deviation from glide slope after leaving the outer marker does not exceed 50 percent of full scale deflection as displayed on the ILS indicator;

(iv) No unusual roughness or excessive attitude changes occur after leaving the middle marker; and

(v) In the case of an airplane equipped with an approach coupler, the airplane is sufficiently in trim when the approach coupler is disconnected at the decision height to allow for the continuation of a normal approach and landing.

(3) Records. During the evaluation program the following information must be maintained by the applicant for the airplane with respect to each approach and made available to the Administrator upon request:

(1) Each deficiency in airborne instruments and equipment that prevented the initiation of an approach,

(ii) The reasons for discontinuing an approach including the altitude above the runway at which it was discontinued.

(iii) Speed control at the 100-foot decision height if auto throttles are used.

(iv) Trim condition of the airplane upon disconnecting the auto coupler with respect to continuation to flare and landing.

(v) Position of the airplane at the middle marker and at the decision height indicated both on a digram of the basic ILS display and a diagram of the runway extended to the middle marker. Estimated touch down point must be indicated on the runway diagram.

(vi) Compatibility of flight director with the auto coupler, if applicable.

(vii) Quality of overall system perform

ance.

(4) Evaluation. A final evaluation of the flight control guidance system is made upon successful completion of the demonstrations. If no hazardous tendencies have been displayed or are otherwise known to exist, the system is approved as installed.

4. Maintenance program. (a) Each maintenance program must contain the following:

(1) A list of each instrument and item of equipment specified in section 2 of this Appendix that is installed in the airplane and approved for Category II operations, including the make and model of those specified in section 2(a).

(2) A schedule that provides for the performance of inspections under subparagraph (5) of this paragraph within 3 calendar months after the date of the previous inspection. The inspection must be performed by a person authorized by Part 43 of this chapter, except that each alternate inspection may be replaced by a functional flight check. This