to, and retained in, the requirements because it was recognized that there are a limited number of electrical functions that are needed when the master switch is in the position. The requirements of this section provide for the safe installation of these circuits. The five-ampere load restriction of a new paragraph (b)(3) was added because the FAA was made aware of an installation in which this provision was being used to circumvent the master switch arrangements by using up to four fiveampere fuses to supply a 20-ampere circuit. This restrictive provision should make it clear that such installations are not permitted.”
The proposal in NPRM 90-23 was revised by Final Rule, Docket 26344 as follows:
“This proposes to amend Sec. 23.1361 to clarify the requirement for the master switch arrangement and to permit new generations of engines to operate with the master switch turned off. No comments were received; however, an editorial revision has been made that revises the text of the last sentence from one that permits the master switch arrangement to use separate switches to text that provides requirements for the master switch arrangement if separate switches are installed.
This proposal is adopted with the aforementioned change.”
Amendment 23-49 and Subsequent
This amendment is explained by Final Rule, Docket 29806 as follows: “To harmonize with the JAR this proposal would revise Sec. 23.1361(c) by making an editorial change to remove the last two words of the paragraph that read "in flight."
This change will not alter the meaning of the requirement.”
23.1365 Electric cables and equipment
The corresponding rule in CAR 3 is CAR 3.693.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.21.
Original Issue and Subsequent
Section 23.1365 requires that each cable that would overheat in a circuit overload or malfunction be at least flame resistant and not emit dangerous quantities of toxic fumes. The compliance methods for the flame resistance requirement are in AC 23-2, “Flammability Tests.” To aid in meeting the toxic fume requirement, the FAA has removed MIL-W-5086 wire from the listing of approved wires in AC 43.13-1B, Change 1, “Acceptable Methods, Techniques, and Practices⎯Aircraft Inspection and Repair.”
See guidance in section 23.853 of this AC for flammability.
Amendment 23-14 and Subsequent
The flame resistance and toxic fume requirements are applicable to equipment associated with the cable as well as the cable itself. A proposed revision to NPRM 71-13 explains this amendment as follows: “This proposal is considered necessary because of the higher powered electrical systems being installed in part 23 airplanes. Such systems are more likely to cause heat damage and the emission of toxic fumes in the event of malfunction.”
Amendment 23-43 and Subsequent
A proposed revision to NPRM 90-23 explains this amendment as follows: “This proposal provides crashworthiness standards for electrical cables. It would require that electrical cables be designed to allow a reasonable degree of deformation and stretching without failure and be isolated from flammable fluid lines or must be shrouded in insulated flexible conduit.”
The proposal in NPRM 90-23 was changed by Final Rule, Docket 26344, and is explained as follows: “One commenter believes the word "isolated" used in proposed Sec. 23.1365(c)(1) is not compatible with current practices and suggests the word "separated" be used in its place. The FAA reviewed this recommended change and agrees that "separate" better describes the current practice of keeping electrical cables and flammable fuel lines spaced a part. This proposal is adopted with the aforementioned change.”
Amendment 23-49 and Subsequent
The proposed revision to NPRM 94-21 has the following explanation for this amendment: “This proposal would revise Sec. 23.1365(b) and would add three new paragraphs.
Section 23.1365(b) would be revised in relation to proposed new Sec. 23.1359(c), which would require self-extinguishing insulated electrical wires and cables.
Current Sec. 23.1365(b) requires that cable and associated equipment that would overheat in the event of circuit overload or fault must be flame resistant and may not emit dangerous quantities of toxic fumes. The proposed revisions to Sec. 23.1365(b) would remove the reference to electrical cables from the flame resistance requirement since the cables would be required to have self-extinguishing insulation under Sec. 23.1359(c). The requirement for electrical cables and the associated equipment that would overheat to not emit dangerous quantities of toxic fumes has been retained.
The text of Sec. 23.1365(b) that includes the words "at least flame resistant" would also be revised by removing the words "at least". The removed words implied that there were burn requirements, other than the ones in this section that must be met.
The three paragraphs that would be added by this proposal would require: (1) The identification of electrical cables, terminals, and connectors; (2) the protection of electrical cables from damage by external sources; and (3) installation criteria for cables that cannot be protected by a circuit protection device.
As identified in the discussion of proposed Sec. 23.1359, there is an increasing use of electrical systems in part 23 airplanes. The resulting increase in the number of electrical wires used in part 23 airplanes makes proper installation difficult. The proposal for electrical cable identification would provide better assurance that the cables will be correctly installed initially and correctly reinstalled when airplane maintenance or modifications are accomplished. The other proposed new requirements would provide installation criteria that will ensure the protection of cables under circumstances that can be expected from the increased use of electrical systems.”
23.1367 Switches
The corresponding rule in CAR 3 is CAR 3.694.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.22.
Original Issue and Subsequent
This rule was adopted on February 1, 1965 as a recodification of CAR 3.694 and
3.695.
Switches are required to be labeled for operation and the circuit controlled. A switch that operates by a push once for ON and once for OFF should be labeled “PUSH OFF/ON.”
Switches are also required to be accessible to the flight crew. The intent of this rule is that those switches that are installed in the cockpit should be accessible to a flight crewmember if manual operation is necessary for safety of flight.
LIGHTS
23.1381 Instrument lights
No policy available as of September 30, 2003.
This rule was adopted on February 1, 1965 as a recodification of CAR 3.696 and
3.697.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.23.
23.1383 Taxi and landing lights
The corresponding rules in CAR 3 are CAR 3.698 and 3.699.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.24.
Amendment 23-49 and Subsequent
This amendment was revised to add taxi lights to the original rule. A proposed revision to NPRM 94-21 explains this amendment as follows: “The landing light requirements of Sec. 23.1383 would be revised by adding taxi lights to this section.
When the landing light requirements were included in the normal, utility, acrobatic, and commuter category requirements, the same lights were used for both night landing and taxiing of the airplane. Due to availability of different types of lights, separate lights are now frequently installed for landing and for taxiing. Including the word "taxi" in the heading would clarify that the requirements cover both kinds of lights.
Current Sec. 23.1383(a), which requires the lights to be acceptable, would be deleted because it is unnecessary to state this. All lights that are found to meet the requirements of this section and other directly related airworthiness requirements are acceptable. The paragraphs would be redesignated accordingly.
Current Sec. 23.1383(b)(3) requires that a landing light must be installed to provide enough light for a night landing. Proposed Sec. 23.1383(c) would revise "night landing" to "night operation" since the requirements would also cover taxiing and parking. Proposed new paragraph (d) would require the lights to be installed so that they do not cause a fire hazard. This clarifies the need for such an evaluation.”
23.1385 Position light system installation
The corresponding rule in CAR 3 is CAR 3.700.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.25.
Original Issue and Subsequent
Guidance on light measurements can be found in AC 20-74, “Aircraft Position and Anticollision Light Measurements.” Additional guidance on position lights can be found in AC 20-30B, “Aircraft Position Light and Anticollision Light Installation.”
Guidance on flame resistance can be found in AC 23-2, “Flammability Tests.”
The intent of the rule in § 23.1357 is met for installations that integrate position and anticollision lights on one wire when no single failure can cause the loss of any of the following:
(a) More than all anticollision lights.
(b) More than all position lights.
(c) More than one position light and the anticollision light adjacent to it.
Position lights are not required for airplanes limited to day VFR operation (placarded for VFR day). If approved for night VFR or IFR, then position lights are required according to §§ 23.1385 through 23.1395. They should be listed on the kinds of operation equipment list (§ 23.1559(b)) and included in the limitations section of the AFM (§ 23.1583(h)).
Amendment 23-17 and Subsequent
A proposed revision to NPRM 75-10 explains this amendment as follows: “By amending Sec. 23.1385 in a manner substantively identical to that proposed for Sec.
25.1385. The proposal would revise Sec. 25.1385 to make more clear the circumstances in which forward and rear position lights may be located at other than the appropriate airplane extremities.”
The proposed amendment was revised by Final Rule, Docket 14324, and is explained as follows: “Two commentators, also suggested that proposed Secs. 23.1385(c) and
25.1385(c) be revised to permit a new position light to be installed on each wing tip.
The FAA agrees that further study is necessary to develop factors of general applicability for position lights on all aircraft but that a rear position light as far aft 284
as practical on each wing tip of an airplane is a reasonable alternative location.
Accordingly, proposed Secs. 23.1385(c) and 25.1385(c) have been revised.”
Amendment 23-43 and Subsequent
A proposed revision to NPRM 90-23 explains this amendment as follows: “This proposal clarifies the location requirements for the position lights, deletes the requirement for a single circuit, and removes the redundant statement "must be approved". Conference proposal 464 recommended changing paragraph (b) so the location of position lights can be compatible with airplane configurations such as tandem wing, canards, and swept wings. The words "forward on the airplane" in paragraph (b) have been interpreted to mean the first 50 percent of the airplane length.
Conference proposal 465 recommended deleting paragraph (d) since it had been interpreted to prohibit multiple circuits from being installed. A consensus at the conference supported both of these recommendations.
The FAA has further studied these issues and concludes clarification is required and that the proposed requirements are substantively equivalent to the current rule.”
23.1387 Position light system dihedral angles
The corresponding rule in CAR 3 is CAR 3.701.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.26.
Amendment 23-12 and Subsequent
This amendment is explained by Final Rule, Docket 11479 as follows: “Sections
23.1387, 25.1387, 27.1387, and 29.1387 presently require, in part, that the rear position light show unbroken light within a dihedral angle formed by two intersecting vertical planes making angles of 70° to the right and left, respectively, of a vertical plane passing through the longitudinal axis. Other related provisions of the regulations require that the rear position light be mounted as far aft as practicable.
In certain aircraft designs incorporating swept vertical tail surfaces, the obstructed visibility requirements may be met only by locating the rear position light on the trailing edge of the rudder. Because this location may cause a number of problems, including complex electrical installation and adverse rudder flutter characteristics, some manufacturers consider the aft most tip of the fuselage to be a more suitable location. Thus, while the rudder position may be farther aft, the fuselage location is as far aft as is practicable. At the same time, however, the fuselage location does not comply with the obstructed visibility requirements where parts of the rudder and vertical stabilizer of a swept tail project into space required to be unobstructed.
For aircraft having this problem, the obstruction resulting from use of the aft fuselage location would, nevertheless, be relatively small because of the thinness of the vertical stabilizer and rudder. Moreover, the obstruction occurs at a high angle above the longitudinal axis of the aircraft so that except for the near-zenith position, the rear position light shows unbroken light.
Related requirements for position lights allow diminishing light intensity with increasing angle above or below the horizontal. Thus, for angles 40° and more above and below the horizontal plane, the position light intensity need be only 5 percent of the light intensity in the horizontal plane. This provision thus recognizes that the significance of a position light decreases as zenith is approached.
A provision similar to that being here established for the rear position light already exists with respect to the anticollision light. In this connection, minor visibility obstructions permitted in the rearward direction in the field of coverage of the anticollision light have been determined not to be detrimental to safety.
In light of the foregoing, obstructions within the dihedral angle in which the rear position light must show, which do not exceed 0.04 steradians in coverage and which occur within 30- of a vertical line through the rear position light, would not adversely affect safety. In addition, these amendments permitting minor obstructions in the field of coverage of rear position lights are consistent with the provisions of Secs.
23.1385(c), 25.1385(c), 27.1385(c), and 29.1385(c) which recognize practicable considerations in the location of rear position lights.”
Amendment 23-43 and Subsequent
This amendment removed the words “forward and rear” from paragraph (a). These changes are necessary for compatibility with revised § 23.1385.
23.1389 Position light distribution and intensities
The corresponding rule in CAR 3 is CAR 3.702.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.27.
Amendment 23-43 and Subsequent
A proposed revision to NPRM 90-23 explains this amendment as follows: “Section
23.1389 is amended in paragraph (b) by removing words "Forward and rear" from the heading, by changing the word "position" in the heading to read "Position", and by removing the words "forward and rear" from the first sentence; in paragraph
(b)(3) by removing the word "forward" in the last sentence and inserting in its place the words "left and right".
These changes are necessary for compatibility with revised § 23.1385.
23.1391 Minimum intensities in the horizontal plane of position lights
The corresponding rule in CAR 3 is CAR 3.702.
The corresponding rule in the Airship Design Criteria, FAA-P-8110-2, Change 2, is section 6.28.
Amendment 23-43 and Subsequent
A proposed revision to NPRM 90-23 explains this amendment as follows: “Section
23.1391 is amended in the section heading by removing the words "forward and rear" and in the table by removing the words "(forward red and green)" and inserting in their place "(red and green)".”
These changes are necessary for compatibility with revised § 23.1385.