23.1367 Switches
The corresponding rule in CAR 3 is CAR 3.694.
The corresponding airworthiness criteria is section 6.22, Airship Design Criteria, FAA-P-8110-2, Change 2.
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.
294 Section 4. Lights
23.1381 Instrument lights
No policy available as of December 31, 2007.
This rule was adopted on February 1, 1965 as a recodification of CAR 3.696 and
3.697.
The corresponding airworthiness criteria is section 6.23, Airship Design Criteria, FAA-P-8110-2, Change 2.
23.1383 Taxi and landing lights
The corresponding rules in CAR 3 are CAR 3.698 and 3.699.
The corresponding airworthiness criteria is section 6.24, Airship Design Criteria, FAA-P-8110-2, Change 2.
Original Issue and Subsequent
Installation of Non-Required Lights
Summary
This guidance pertains to FAA certification policy on 14 CFR, part 23. Neither Title 14 CFR, part 23 nor the Airship Design Criteria (ADC) have airworthiness standards for non-required lights. Applicants have requested certification of non-required recognition lights for part 23 airplanes. These applicants assert that taxi, landing and recognition lights have been approved without reference to their effect on the field of coverage for required position and anticollision lights. Applicants also assert that these lights have been approved without regard to their effect on the Electromagnetic Interference (EMI) issues they present for other installed equipment.
Other applicants have requested approval of non-required lights that are intended to illuminate parts of an aircraft (logo lights). Previously, these lights have also been approved without regard to their effect on required lights or the EMI issues they present for installed equipment.
Title 14 CFR, part 23, has one section, § 23.1383, for taxi and landing lights. Section
6.24 of the Airship Design Criteria contains requirements for landing lights. Taxi lights are designed for the taxi phase of flight; therefore, reducing the area covered by required position or anticollision lights in that phase is acceptable. Landing lights are designed for use in the approach and landing phases of flight; therefore, reducing the area covered by required position or anticollision lights in those phases is acceptable.
Part 23 does not require recognition lights which are brighter than position and anticollision lights. Issues of intensity, EMI, and hazard analysis for these lights must be addressed. Recognition lights face forward. With two aircraft approaching each other on nearly nose-to-nose courses, the aircraft with recognition lights will be seen earlier than the aircraft with only the required lights. Recognition lights are acceptable if they supplement but do not reduce the required field of coverage of position lights or anticollision lights, do not cause a hazard, and do not cause EMI.
Part 23 also has no requirements for lights used to illuminate parts of an aircraft (Logo Lights). They also have issues of intensity, EMI, and hazard analysis that must be addressed. If such non-required lights are installed, they must meet the same requirements as recognition lights regarding their effect on the required field of
296 coverage of required lights, EMI concerns, and hazard analysis. If they are limited to use on the ground, then their effect on required lights is not an issue.
Applicability
This guidance pertains to14 CFR, part 23, §§ 23.1383 through 23.1395, and § 23.1401 for installing required and non-required lights on part 23 aircraft. It applies to normal, utility, acrobatic, and commuter category airplanes. It also applies to nonrigid airships (ADC sections 6.24 through 6.30 and 6.32) certificated in the normal category (14 CFR, part 21, § 21.17(b)) with nine passenger seats or less.
References
23.863 Flammable fluid fire protection
23.1301 Function and installation
23.1309 Equipment, systems, and installation AC 20-30B Aircraft Position Light a nd Anticollision Light Installations AC 20-74 Aircraft Position and An ticollision Light Measurements
Guidance
The lights proposed for use as non-required recognition and logo lights are typically much brighter than the intensity requirements of position and anticollision lights.
These lights have a potential to interfere with the field of coverage required for position and anticollision lights. Anticollision lights are installed to allow a pilot in an aircraft on an intersecting course to see the traffic. Position lights are red on the left side and green on the right side to allow a pilot in an aircraft on an intersecting course to determine the direction of flight of the traffic.
If the installation of non-required lights does not affect the field of coverage, the required intensities of the position and anticollision lights will not be reduced. Nonrequired lights:
1. should not cause any dangerous glare visible to the pilots,
2. should not cause serious halation to the pilots,
3. should not cause a fire hazard, and
4. should not cause EMI with previously installed equipment.
Title 14 CFR, part 23, has no rules for recognition or logo lights; it has one section, § 23.1383, for taxi and landing lights. Section 6.24 of the Airship Design Criteria
297 contains requirements for landing lights. Taxi lights are designed for the taxi phase of flight; therefore, reducing the area covered by required position or anticollision lights is acceptable. Landing lights are designed for use in the approach and landing phases of flight; therefore, reducing the area covered by required position or anticollision lights is acceptable. Use of recognition lights as taxi or landing lights would require compliance with § 23.1383. Logo lights limited to use on the ground may be approved without regard to their effect on required position and anticollision lights.
Hazard Analysis
The required position and anticollision lights are installed for use by pilots of other aircraft who need to be able to see and determine the flight path of an aircraft from the required lights. The § 23.1309 Hazard Analysis must consider the hazard of a pilot on an intersecting course who:
1. Does not see the traffic due to non-required lights, or
2. Cannot determine the flight path of traffic throughout the covered area, as required by §§ 23.1387 and 23.1401, for position and anticollision lights.
Any non-required light that is not limited to use on the ground or in the landing phase must:
1. Perform its intended function according to § 23.1301, and
2. Not present a hazard above “No Safety Effect” for a non-required light installation according to the requirements of § 23.1309; or
3. If the hazard of a non-required light installation is determined to be above “No Safety Effect,” the applicant must request an ELOS to the field of coverage rules for position and anticollision lights.
Electromagnetic Interference
EMI is a concern from two points:
1. Unshielded wiring from the installed li ghting system wires to the non-required lights could act as an antenna and affect other installed equipment, and
2. The non-required lights can be a source of EMI.
Number 1 above is a concern for both Light Emitting Diode (LED) lights and High Intensity Discharge (HID) lights. Number 2 above is a concern for HID lights.
298 For a Supplemental Type Certificate (STC) for one model of aircraft, the applicant must verify that all installed equipment is unaffected by operation of the non-required lights. The concern for antenna EMI requires a ground test. The EMI of the lights may be verified by either a ground test or by environmental bench testing, under RTCA/DO-160F, Sections 15, Magnetic Effect, and 21, Emission of Radio Frequency Energy.
For an Approved Model List (AML) STC, environmental bench testing under RTCA/DO-160F, Sections 15 and 21, is required unless the applicant performs EMI ground testing on all aircraft listed on the AML. Also, an AML STC must include EMI shielding of the non-required wiring installation unless the applicant performs EMI ground testing on all aircraft listed on the AML.
Field of Coverage
Part 23 does not require recognition lights. They face forward and will typically be brighter than required lights in the forward direction. Therefore, when two aircraft are on nearly nose-to-nose courses, the aircraft with the recognition lights will be seen earlier than it would be with only the required lights. Installed recognition lights may increase the field of coverage or may account for part of the required field of coverage, but these lights must not reduce the area covered by anticollision lights or position lights for aircraft approaching from other than nearly nose-to-nose directions.
In addition, Part 23 does not require logo lights, but they may also be used in all phases of flight. Normally, these lights face toward the tail, but whatever the orientation they cannot reduce the field of coverage of required lights.
Section 23.1387, Position light system dihedral angles, requires:
1. Left (L) from two intersecting vertical pl anes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first, as viewed when looking forward along the longitudinal axis.
2. Right (R) from two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the right of the first, as viewed when looking forward along the longitudinal axis.
3. Aft (A) from two intersecti ng vertical planes making angles of 70 degrees left and right respectively to a vertical plane passing through the longitudinal axis of the aircraft as viewed when looking aft along the longitudinal axis.
Wing mounted recognition lights do not affect the Aft dihedral angle, but these lights could affect Left and Right angles. Logo lights could affect the Aft dihedral angle.
In § 23.1401(b), Anticollision light system, the field of coverage requires the light to be visible from 75 degrees above and below a horizontal plane with an exception for
299 the rear facing direction. An anticollision light mounted on the fuselage or vertical fin and aft of the recognition light will not be affected in the rear facing direction. A ground test in a darkened hangar should show that either the recognition light or anticollision light is visible 75 degrees above and below the horizontal plane from the front of the plane. A wing mounted anticollision light should be verified both forward and rearward.
For a logo light, a ground test in a darkened hangar should show that either the logo light or anticollision light is visible 75 degrees above and below the horizontal plane from the front of the airplane.
Handling and Performance
If the non-required light installation extends into the airstream, the applicant must perform flight testing to verify compliance to applicable sections in 14 CFR, part 23, Subpart B.
Applicants should expect that the certificating officials will consider this information when making findings of compliance relevant to new certificate actions. Also, as with all advisory material, this guidance identifies one means, but not the only means, of compliance.
Amendment 23-49 and Subsequent
This amendment was revised to add taxi lights to the original rule. A proposed revision in 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 airworthiness criteria is section 6.25, Airship Design Criteria, FAA-P-8110-2, Change 2.
See § 23.1383 for guidance on non-required light installations.
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 23-2A, “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:
1. More than all anticollision lights.
2. More than all position lights.
3. More than one position light and th e 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 in 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
301 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 in 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 airworthiness criteria is section 6.26, Airship Design Criteria, FAA-P-8110-2, Change 2.
See § 23.1383 for guidance on non-required light installations.
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.
303 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 § 23.1387(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 airworthiness criteria is section 6.27, Airship Design Criteria, FAA-P-8110-2, Change 2.
See § 23.1383 for guidance on non-required light installations.
Amendment 23-43 and Subsequent
A proposed revision in 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.