9 that the pilot will be able to see the required visual references using the EFVS at the destination. The demonstrated performance of the EFVS defines the EFVS operational minimums specified in the operator’s OpSpec or LOA for EFVS operations. The OpSpec for part 121, 125, or 135 operators and the LOA for part 125 Letter of Deviation Authority (LODA) holders authorizes a visibility for dispatching or releasing a flight and for beginning or continuing an approach. Paragraph 10.2 provides additional information on how to obtain or amend this authorization.
4 EFVS OPERATIONAL CONCEPTS.
4.1 EFVS Operations to Touchdown and Rollout (§ 91.176(a)).
4.1.1 Aircraft Eligibility.
4.1.1.1 An EFVS installed on a U.S.-registered aircraft used to conduct an EFVS operation to touchdown and rollout must be operable and must conform to an FAA-type design approval (a type certificate (TC), amended TC, or Supplemental Type Certificate (STC)). A foreign-registered aircraft used to conduct EFVS operations that does not have an FAA-type design approval must be equipped with an EFVS that has been approved by either the State of the Operator or the State of Registry to meet the requirements of ICAO Annex 6.
4.1.1.2 The EFVS must meet the requirements in § 91.176(a)(1). These requirements are described in paragraphs 4.1.1.3 through 4.1.1.7 and include:
1. Imaging sensors that display the forward external scene to the pilot. These may include but are not limited to FLIR, millimeter wave radiometry, millimeter wave radar, or low-light level image intensification.
2. A display that presents the aircraft flight information, features, and characteristics required by the regulations such that they are clearly visible to the pilot flying (PF) in his or her normal position and line of vision looking forward along the flightpath. This is typically a HUD, but could also be a head-worn display if such a display provides all of the required information and conforms to the out-the-window view. An HDD does not meet the regulatory requirement for the EFVS display element because it is not a head-up presentation and does not allow the pilot to seamlessly incorporate the external scene as it becomes visible using natural vision.
4.1.1.3 At a minimum, the EFVS must display the following specific aircraft flight information:
• Airspeed;
• Vertical speed;
• Aircraft attitude;
• Heading;
• Altitude;
• Height above ground level (AGL);
• Command guidance as appropriate for the approach to be flown;
• Path deviation indications;
• Flight Path Vector (FPV) cue;
• Flight Path Angle Reference Cue (FPARC); and
• Flare prompt or flare guidance, as appropriate to the aircraft.
4.1.1.4 The regulations also specify that the EFVS imagery, attitude symbology, FPV, FPARC, and other cues that are referenced to the imagery and external scene topography must be conformal. That is, they must be aligned with and scaled to the external view. In addition, the FPARC must be selectable by the pilot to the desired descent angle for the approach and be suitable for monitoring the vertical flightpath of the aircraft. The EFVS must display the sensor imagery and aircraft flight information and flight symbology so that they do not adversely obscure the pilot’s outside view or field of view through the cockpit window. The vision system must provide a means to allow the pilot using the display to immediately deactivate and reactivate the vision system imagery, on demand, without removing the pilot’s hands from the primary flight controls or thrust controls. Finally, the display characteristics and dynamics must be suitable for manual control of the aircraft.
4.1.1.5 The EFVS must present height AGL such as that provided by a radio altimeter (RA) or another device capable of providing equivalent performance.
The supplementary information provided by an RA below 100 feet contributes to altitude awareness and can be used to help perform the flare and landing during EFVS operations that are conducted to touchdown and rollout.
4.1.1.6 For aircraft other than rotorcraft, the EFVS must present flare prompt or flare guidance, as appropriate to the aircraft. As specified in AC 20-167, Airworthiness Approval of Enhanced Vision System, Synthetic Vision System, Combined Vision System, and Enhanced Flight Vision System Equipment, each applicant for type design approval should demonstrate acceptable touchdown performance for their particular EFVS implementation using either flare prompt or flare guidance. This requirement is necessary to provide the pilot with additional information to conduct the flare maneuver during conditions of low visibility that may be encountered during EFVS operations to touchdown and rollout.
4.1.1.7 When a minimum flightcrew of more than one pilot is required, the aircraft must also be equipped with a display that provides the pilot monitoring (PM) with EFVS sensor imagery. Any symbology displayed must not adversely obscure the sensor imagery of the runway environment. The PM display may be a HUD, an HDD, or a head-mounted display.
4.1.1.8 An operator can determine the eligibility of their aircraft by referring to the Airplane Flight Manual (AFM) (or Airplane Flight Manual Supplement (AFMS)) or the Rotorcraft Flight Manual (RFM) (or Rotorcraft Flight Manual Supplement (RFMS)). Aircraft that have been shown to meet the requirements for EFVS approach operations to touchdown and rollout will have in their AFM(S) or RFM(S) a statement of compliance to AC 20-167 as an EFVS Landing System or an EFVS Landing and Rollout System.
4.1.1.8.1 An EFVS Landing System has been demonstrated to land and roll out while all system components are working, but may have failure modes that result in the loss of EFVS capability. As such, the flight visibility should be adequate to complete the touchdown and rollout or conduct a go-around in the event the system fails. A visibility of RVR 1000 feet is adequate for this purpose.
4.1.1.8.2 An EFVS Landing and Rollout System has been demonstrated to land and roll out while all system components are working, and in the event of any component failure. Such systems can qualify for even lower visibility, since it is very unlikely the pilot would need to revert to natural vision. A landing and rollout system may be dependent on additional equipment, operational, and visibility and visual reference requirements to account for specific equipment characteristics, operational procedures, or approach characteristics.
4.1.1.9 The AFM(S) or RFM(S) may specify limitations applicable to the installed EFVS equipment and may contain information about conditions that were demonstrated during certification of the EFVS. Demonstrated conditions pertinent to the EFVS may consist of sensor performance information or other conditions that were demonstrated during certification in accordance with AC 20-167. (Refer to AC 20-167, Appendix F, Sample Airplane Flight Manual (AFM) Supplement.) An EFVS that meets the criteria for EFVS operations to touchdown may also be used to conduct EFVS operations to 100 feet above the TDZE.
4.1.2 Approaches Approved for EFVS Operations to Touchdown and Rollout.
4.1.2.1 A pilot may conduct an EFVS operation to touchdown and rollout on any Standard Instrument Approach Procedure (SIAP) or special IAP provided the minimums used for the particular approach to be flown include a DA or DH
(e.g., precision or APV approach).
4.1.2.2 A pilot is not permitted to conduct EFVS operations on an instrument approach that has a circle-to-land maneuver. The EFVS may not be used to satisfy the § 91.175(e)(2) requirement that an identifiable part of the airport be distinctly visible to the pilot during a circling maneuver at or above MDA or while descending below MDA from a circling maneuver, or for conducting a visual approach. The pilot must accomplish this using natural vision. A pilot may use an EFVS to supplement natural vision and improve situation awareness at any time.
4.1.2.3 Instrument approach criteria, procedures, and appropriate visual references have not yet been developed for straight-in landing operations below DA/DH under IFR to heliports or platforms. EFVS cannot be used in lieu of natural vision to descend below published minimums on copter approaches to a point in space (PinS) followed by a “proceed visual flight rules (VFR)” visual segment, or on approaches designed to a specific landing site using a “proceed visually” visual segment. Currently, EFVS operations in rotorcraft can be conducted only on IAPs that are flown to a runway.
4.1.2.4 Under § 91.176(a), operators who have been issued OpSpec C073, MSpec MC073, or LOA C073, Vertical Navigation (VNAV) Instrument Approach Procedures (IAP) Using Minimum Descent Altitude (MDA) as a Decision Altitude (DA)/Decision Height (DH), may conduct EFVS operations to touchdown and rollout on certain Nonprecision Approaches (NPA) that use an MDA as a DA/DH in accordance with C073.
4.1.2.5 Sections 91.176 and 91.189 permit an authorized EFVS operation to be conducted during an authorized CAT II or CAT III operation.
4.1.3 Enhanced Flight Visibility Requirements for EFVS Operations to Touchdown and Rollout.
4.1.3.1 For EFVS operations to touchdown and rollout conducted under §§ 91.176,
121.651, 125.381, and 135.225, no person may conduct an EFVS operation in an aircraft, except a military aircraft of the United States, at any airport below the authorized DA/DH to touchdown and rollout, unless the pilot determines that the enhanced flight visibility observed by use of an EFVS is not less than the visibility prescribed in the IAP the pilot is using. The EFVS requirements for enhanced flight visibility under § 91.176(a) were constructed to be analogous to the flight visibility requirements for natural vision under § 91.175(c). To descend below DA/DH or MDA using natural vision under § 91.175(c), a pilot must make a determination that the flight visibility observed from the flight deck is not less than what is prescribed in the IAP being flown. To descend below DA/DH using an EFVS under § 91.176(a), a pilot must make a determination that the enhanced flight visibility observed by using an EFVS is not less than what is prescribed by the IAP being flown.
In terms of determining flight visibility or enhanced flight visibility,
13 the difference is in what the pilot uses to make the determination. In one case, the pilot is using natural vision. In the other case, the pilot is using an EFVS.
4.1.3.2 Understanding the regulatory basis for determining flight visibility and enhanced flight visibility is important. On January 8, 1981, the FAA published 46 FR 2291, Takeoff and Landing Minimums, in which it clarified the conditions under which a pilot may approach and land at an airport when the weather conditions do not allow the pilot to see the runway until shortly before landing (46 FR 2291, at 2287-88). The determination of flight visibility is a separate action from that of identifying required visual references, and is different from ground-reported visibility. Suitable flight visibility is necessary to ensure the aircraft is in a position to continue the approach and land, and to see and avoid any obstructions in the visual segment. On January 9, 2004, the FAA published 69 FR 1620, in which it set forth the requirement for a pilot to determine enhanced flight visibility before descending below DA/DH or MDA. The rationale for determining enhanced flight visibility in the 2004 final rule is similar to the rationale for determining flight visibility in the 1981 final rule. Additionally, the regulatory requirements and pilot tasks associated with both types of operations are similar.
4.1.3.3 It is important to understand that, for a prescribed visibility value, the “sight picture” of the relevant visual references that the pilot can see looking forward along the flightpath from the flight deck should be similar whether the pilot is using natural vision or an EFVS. Even though the reported visibility or the visibility observed using natural vision may be less, as long as the EFVS provides the required enhanced flight visibility and a pilot meets all of the other requirements, the pilot can continue descending below DA/DH using the EFVS. Pilots should receive training on how to assess enhanced flight visibility and what the “sight picture” of relevant visual references should be. How much of the forward scene, consisting of the Approach Light System (ALS) or other elements, a pilot sees at DA/DH under prescribed visibility conditions depends on individual IAP construction (geometry, threshold crossing height (TCH), slant range distance from the flight deck to relevant visual references, etc.), cockpit cutoff angle, and other relevant factors. As visibility conditions decrease, the ability of an EFVS to “see through” those conditions may also decrease depending on what type of EFVS sensor technology is used. It is important to note that there are differences in the appearance and configuration of ALSs and these should be discussed during training as well as during approach briefs. It is the pilot’s responsibility to ensure the enhanced flight visibility is adequate to safely perform the EFVS operation being conducted.
4.1.3.4 The enhanced flight visibility requirement for EFVS operations to touchdown and rollout under § 91.176(a) is also applicable to that portion of the visual segment at and below 100 feet above the TDZE. That is, the enhanced flight visibility cannot be less than what is specified in the IAP being flown from DA/DH through touchdown and rollout.
4.1.4 Visual Reference Requirements for EFVS Operations to Touchdown and Rollout.
4.1.4.1 To descend below DA/DH, the following visual references specified in § 91.176(a)(3)(ii) for the runway of intended landing must be distinctly visible and identifiable to the pilot using the EFVS:
4.1.4.1.1 The ALS (if installed); or
4.1.4.1.2 The following visual references in both items 1 and 2 below:
1. The runway threshold, identified by at least one of the following:
• The beginning of the runway landing surface;
• The threshold lights; or
• The runway end identification lights (REIL).
2. The TDZ, identified by at least one of the following:
• The runway TDZ landing surface;
• The TDZ lights;
• The TDZ markings; or
• The runway lights.
4.1.4.2 The main differences for an EFVS operation compared to an operation using natural vision are that the Visual Glide Slope Indicator (VGSI) lights cannot be used as a visual reference, and the pilot must be able to see both the threshold and TDZ if the approach lights are not visible.
4.1.4.3 At 100 feet above the TDZE of the runway of intended landing and below that altitude, the pilot using EFVS must be able to distinctly see and identify one of the following visual references specified in § 91.176(a)(3)(iii):
• The runway threshold;
• The lights or markings of the threshold;
• The runway TDZ landing surface; or
• The lights or markings of the TDZ.
4.1.4.4 A pilot who conducts an EFVS operation to touchdown and rollout can continue to descend below 100 feet relying solely on the EFVS sensor image to identify the required visual references provided the other operating requirements of § 91.176(a) are met. If the EFVS fails during any portion of the approach, the pilot may not continue unless the requirements for an approach without EFVS are satisfied. For EFVS operations to touchdown and rollout that are authorized to visibilities as low as 1000 RVR, the required
15 visibility ensures that the pilot will have adequate natural vision to continue the approach and land once descending below 100 feet above the TDZE.
4.1.4.5 Table 1, Required Visual References, summarizes the visual references a pilot must see using both natural vision and EFVS.
Table 1. Required Visual References Required Visual References Using Natural Vision Required Visual References Using an Enhanced Flight Vision System (EFVS) Descent below DA/DH or MDA under 14 CFR § 91.175(c) – At least one of the following references using natural vision:
Approach light system (ALS) Threshold Threshold markings Threshold lights Runway end identifier lights (REIL) Visual Approach Slope Indicator (VASI) Touchdown zone (TDZ) TDZ markings TDZ lights Runway Runway markings Runway lights Descent below DA/DH or MDA under § 91.176 (a) or (b) – The following references, using the EFVS:
ALS OR BOTH paragraphs A and B A. The runway threshold, identified by at least one of the following:
Beginning of the runway landing surface, Threshold lights, or REILs AND B. The TDZ, identified by at least one of the following:
Runway TDZ landing surface, TDZ lights, TDZ markings, or Runway lights.
At and below 100 feet above the TDZE under § 91.175(c) – At least one of the following visual references:
ALS, as long as the red terminating bars or red side row bars are also distinctly visible and identifiable Threshold Threshold markings Threshold lights REILs VASI TDZ TDZ markings TDZ lights Runway Runway markings Runway lights At and below 100 feet above the TDZE under § 91.176(a) or (b) – At least one of the following visual references using natural vision for EFVS operations to 100 feet above the touchdown zone elevation (TDZE) or using an EFVS for EFVS operations to touchdown and rollout:
The runway threshold, The lights or markings of the threshold, The runway TDZ landing surface, or The lights or markings of the TDZ.
4.1.5 Go-Around Considerations.
4.1.5.1 During an EFVS operation to touchdown and rollout, a pilot must initiate a go-around at or below DA/DH whenever:
1. The enhanced flight visibility is less than the visibility minimums prescribed for the IAP the pilot is flying;
2. The required visual references for the runway of intended landing are no longer distinctly visible and identifiable to the pilot using the EFVS imagery (or natural vision in the event of EFVS failure);
3. The aircraft is not in a position from which a descent to a landing can be made on the intended runway, at a normal rate of descent, using normal maneuvers; or
4. The descent rate of the aircraft would not allow touchdown to occur within the TDZ of the runway of intended landing.
4.1.6 Other Operating Requirements for EFVS Operations to Touchdown and Rollout.
4.1.6.1 To conduct an EFVS operation to touchdown and rollout, the aircraft must be equipped with, and the PF must use, an operable EFVS as described in paragraph 4.1.1. When a minimum flightcrew of more than one pilot is required, the display of EFVS sensor imagery to the PM provides common situation awareness. The PM would carry out his or her normal approach monitoring tasks and use the display of EFVS sensor imagery to confirm the required visual references, verify visual acquisition of and alignment with the runway of intended landing, and assist in determining that the runway is clear of aircraft, vehicles, or other obstructions. Paragraph 4.1.1.7 and AC 20-167 discuss the requirements applicable to the PM display.
4.1.6.2 Each required pilot flightcrew member must have adequate knowledge of, and familiarity with, the aircraft, the EFVS, and the procedures to be used.
Paragraphs 5 and 6 address pilot training, proficiency and competency checks, recent flight experience, and refresher training requirements.
4.1.6.3 The FAA requires an OpSpec, MSpec, or LOA, as appropriate to the operator, to conduct EFVS operations to touchdown and rollout. Paragraph 10 addresses authorization and operational approval requirements in more detail.
4.2 EFVS Operations to 100 Feet Above the TDZE (§ 91.176(b)).
4.2.1 Aircraft Eligibility.
4.2.1.1 An EFVS installed on a U.S.-registered aircraft used to conduct an EFVS operation to 100 feet above the TDZE must be operable and must conform to an FAA type design approval (a TC, amended TC, or STC). A foreign-registered aircraft used to conduct EFVS operations that does not have
17 an FAA type design approval must be equipped with an EFVS that has been approved by either the State of the Operator or the State of Registry to meet the requirements of ICAO Annex 6.
4.2.1.2 The EFVS must meet the requirements in § 91.176(b)(1). These requirements are described in paragraphs 4.2.1.3 and 4.2.1.4 and include:
1. Imaging sensors that display the forward external scene to the pilot. These may include, but are not limited to, FLIR, millimeter wave radiometry, millimeter wave radar, or in low-light level image intensification.
2. A display that presents the aircraft flight information, features, and characteristics required by the regulations such that they are clearly visible to the PF in his or her normal position and line of vision looking forward along the flightpath. This is typically a HUD, but could also be a head-worn display if such a display provides all of the required information and conforms to the out-the-window view. An HDD does not meet the regulatory requirement for the EFVS display element because it is not a head-up presentation and does not allow the pilot to seamlessly incorporate the external scene as it becomes visible using natural vision.
4.2.1.3 At a minimum, the EFVS must display the following specific aircraft flight information:
• Airspeed;
• Vertical speed;
• Aircraft attitude;
• Heading;
• Altitude;
• Command guidance as appropriate for the approach to be flown;
• Path deviation indications;
• FPV cue; and
• FPARC.
4.2.1.4 The regulations also specify that the EFVS imagery, attitude symbology, FPV, FPARC, and other cues that are referenced to the imagery and external scene topography must be conformal. That is, they must be aligned with and scaled to the external view. In addition, the FPARC must be selectable by the pilot to the desired descent angle for the approach and be suitable for monitoring the vertical flightpath of the aircraft. The EFVS must display the sensor imagery and aircraft flight information and flight symbology so that they do not adversely obscure the pilot’s outside view or field of view through the
18 cockpit window. The vision system must provide a means to allow the pilot using the display to immediately deactivate and reactivate the vision system imagery, on demand, without removing the pilot’s hands from the primary flight controls or thrust controls. Finally, the display characteristics and dynamics must be suitable for manual control of the aircraft.
4.2.1.5 Unlike an EFVS that is used to conduct EFVS operations to touchdown and rollout, an EFVS that is used to conduct EFVS operations to 100 feet is not required to have an RA, is not required to display flare prompt or flare guidance, and does not have to provide a PM display.
4.2.1.6 An operator can determine the eligibility of their aircraft by referring to the AFM(S) or RFM(S). Aircraft that have been shown to meet the requirements for EFVS approach operations to 100 feet above the TDZE will have in their AFM(S) or RFM(S) a statement of compliance to AC 20-167 as an EFVS Approach System.
4.2.1.6.1 An EFVS approach system has been demonstrated to conduct approach operations to 100 feet above the TDZE while all system components are working, but may have failure modes that result in the loss of EFVS capability. Above 100 feet above the TDZE, the pilot is expected to conduct a go-around if the EFVS fails. Descent below 100 feet above the TDZE through touchdown and rollout is conducted using natural vision, so any failure of the EFVS should not prevent the pilot from completing the approach and landing.
4.2.1.7 The AFM(S) or RFM(S) may specify limitations applicable to the installed EFVS equipment and may contain information about conditions that were demonstrated during certification of the EFVS. Demonstrated conditions pertinent to the EFVS may consist of sensor performance information or other conditions that were demonstrated during certification in accordance with AC 20-167. (Refer to AC 20-167, Appendix F.) An EFVS that has been certified only for EFVS operations to 100 feet above the TDZE cannot be used to conduct EFVS operations to touchdown and rollout.
4.2.1.8 The AFM(S) or RFM(S) for an EFVS that was approved prior to December 13, 2016 may reference § 91.175(l). This means the EFVS was certified for EFVS operations to 100 feet above the TDZE. The regulations pertaining to EFVS operations to 100 feet above the TDZE were previously located in § 91.175(l) and were later moved to § 91.176(b).
4.2.2 Approaches Approved for EFVS Operations to 100 Feet Above the TDZE.
4.2.2.1 A pilot may conduct an EFVS operation to 100 feet above the TDZE on any SIAP or special IAP, except for a circling approach. The EFVS may not be used to satisfy the § 91.175(e)(2) requirement that an identifiable part of the airport be distinctly visible to the pilot during a circling maneuver at or above MDA or while descending below MDA from a circling maneuver, or for
19 conducting a visual approach. The pilot must accomplish this using natural vision. A pilot may use an EFVS to supplement natural vision and improve situation awareness at any time.
4.2.2.2 Instrument approach criteria, procedures, and appropriate visual references have not yet been developed for straight-in landing operations below DA/DH or MDA under IFR to heliports or platforms. EFVS cannot be used in lieu of natural vision to descend below published minimums on copter approaches to a PinS followed by a “proceed VFR” visual segment, or on approaches designed to a specific landing site using a “proceed visually” visual segment.
Currently, EFVS operations in rotorcraft can be conducted only on IAPs that are flown to a runway.
4.2.2.3 Operators who have been issued OpSpec C073, MSpec MC073, or LOA C073 may conduct EFVS operations to 100 feet above the TDZE on certain NPAs that use an MDA as a DA/DH in accordance with C073.
4.2.3 Enhanced Flight Visibility Requirements for EFVS Operations to 100 Feet Above the TDZE.
4.2.3.1 For EFVS operations to 100 feet above the TDZE conducted under §§ 91.176,
121.651, 125.381, and 135.225, no person may conduct an EFVS operation in an aircraft, except a military aircraft of the United States, at any airport below the authorized DA/DH or MDA to 100 feet above the TDZE unless the pilot determines that the enhanced flight visibility observed by use of an EFVS is not less than the visibility prescribed in the IAP the pilot is using. The EFVS requirements for enhanced flight visibility under § 91.176(b) were constructed to be analogous to the flight visibility requirements for natural vision under § 91.175(c). To descend below DA/DH or MDA using natural vision under § 91.175(c), a pilot must make a determination that the flight visibility observed from the flight deck is not less than what is prescribed in the IAP being flown. To descend below DA/DH or MDA using an EFVS under § 91.176(b), a pilot must make a determination that the enhanced flight visibility observed by using an EFVS is not less than what is prescribed by the IAP being flown. The difference between determining flight visibility and enhanced flight visibility is in what the pilot uses to make the determination.
In one case, the pilot is using natural vision. In the other case, the pilot is using an EFVS. The regulatory basis for enhanced flight visibility is discussed in more detail in paragraph 4.1.3.2.
4.2.3.2 It is important to understand that, for a prescribed visibility value, the “sight picture” of the relevant visual references that the pilot can see looking forward along the flightpath from the flight deck should be similar whether the pilot is using natural vision or an EFVS. An EFVS often produces the required enhanced flight visibility when the reported visibility or the visibility observed using natural vision is much less. The point of this discussion is that even though the reported visibility or the visibility observed using natural vision
20 may be less, as long as the EFVS provides the required enhanced flight visibility and a pilot meets all of the other requirements, the pilot can continue descending below DA/DH or MDA using the EFVS. Pilots should receive training on how to assess enhanced flight visibility and the “sight picture” for relevant visual references. How much of the forward scene, consisting of the ALS or other elements, a pilot sees at DA/DH or MDA under prescribed visibility conditions depends on individual IAP construction (geometry, TCH, slant range distance from the flight deck to relevant visual references, etc.), cockpit cutoff angle, and other relevant factors. As visibility conditions decrease, the ability of an EFVS to “see through” those conditions may also decrease depending on what type of EFVS sensor technology is used. It is important to note that there are differences in the appearance and configuration of ALSs and these should be discussed during training as well as during approach briefs. It is the pilot’s responsibility to ensure the enhanced flight visibility is adequate to safely perform the EFVS operation being conducted.
4.2.3.3 At and below 100 feet above the TDZE, a pilot must transition to natural vision to identify the required visual references in order to continue descending. In this portion of the visual segment, the flight visibility using natural vision has to be sufficient for one of the required visual references specified in § 91.176(b)(3)(iii) to be distinctly visible and identifiable.
The enhanced flight visibility requirement, based on the visibility for the IAP, also applies below 100 feet even though the EFVS cannot be used to identify required visual references below 100 feet.
4.2.4 Visual Reference Requirements for EFVS Operations to 100 Feet Above the TDZE.
4.2.4.1 To descend below DA/DH or MDA, the following visual references specified in § 91.176(b)(3)(ii) for the runway of intended landing must be distinctly visible and identifiable to the pilot using the EFVS:
4.2.4.1.1 The ALS (if installed); or
4.2.4.1.2 The following visual references in both items 1 and 2 below:
1. The runway threshold, identified by at least one of the following:
• The beginning of the runway landing surface;
• The threshold lights; or
• The REILs.
2. The TDZ, identified by at least one of the following:
• The runway TDZ landing surface;
• The TDZ lights;