AIM

4/3/14

5−4−57

Arrival Procedures

climb restrictions, charted obstacles, published

obstacle departure procedure, takeoff visual climb

requirements as expressed by nonstandard takeoff

minima, other traffic expected to be in the vicinity, or

other factors not specifically expressed by the ap-

proach procedures.

5

−

4

−

22. Use of Enhanced Flight Vision

Systems (EFVS) on Instrument Approaches

An EFVS is an installed airborne system which uses

an electronic means to provide a display of the

forward external scene topography (the applicable

natural or manmade features of a place or region

especially in a way to show their relative positions

and elevation) through the use of imaging sensors,

such as forward looking infrared, millimeter wave

radiometry, millimeter wave radar, and/or low light

level image intensifying. The EFVS imagery is

displayed along with the additional flight information

and aircraft flight symbology required by 14 CFR

91.175 (m) on a head−up display (HUD), or an

equivalent display, in the same scale and alignment as

the external view and includes the display element,

sensors, computers and power supplies, indications,

and controls. The display is typically presented to the

pilot by means of an approved HUD.

a. Basic Strategy Using EFVS.

When flying an

instrument approach procedure (IAP), if the runway

environment cannot be visually acquired at decision

altitude (DA) or minimum descent altitude (MDA)

using natural vision, then a pilot may use an EFVS to

continue descending down to 100 feet above the

Touchdown Zone Elevation (TDZE), provided all of

the visibility requirements of 14 CFR part 91.175 (l)

are met. The primary reference for maneuvering the

aircraft is based on what the pilot sees through the

EFVS. At 100 feet above the TDZE, a pilot can con-

tinue to descend only when the visual reference

requirements for descent below 100 feet can be seen

using natural vision (without the aid of the EFVS). In

other words, a pilot may not continue to rely on the

EFVS sensor image to identify the required visual

references below 100 feet above the TDZE. Support-

ing information is provided by the flight path vector

(FPV), flight path angle (FPA) reference cue, on-

board navigation system, and other imagery and

flight symbology displayed on the EFVS. The FPV

and FPA reference cue, along with the EFVS imagery

of the Touchdown Zone (TDZ), provide the primary

vertical path reference for the pilot when vertical

guidance from a precision approach or approach with

vertical guidance is not available.

1. Straight

−In Instrument Approach

Procedures.

An EFVS may be used to descend

below DA or MDA from any straight−in IAP, other

than Category II or Category III approaches,

provided all of the requirements of 14 CFR part

91.175 (l) are met. This includes straight−in precision

approaches, approaches with vertical guidance (for

example, LPV or LNAV/VNAV), and non−precision

approaches (for example, VOR, NDB, LOC, RNAV,

GPS, LDA, SDF, etc.).

2. Circling Approach Procedure.

An IAP

with a circle−to−land maneuver or circle−to−land

minimums does not meet criteria for straight−in

landing minimums. While the regulations do not

prohibit EFVS from being used during any phase of

flight, they do prohibit it from being used for

operational credit on anything but a straight−in IAP

with straight−in landing minima. EFVS must only be

used during a circle−to−land maneuver provided the

visual references required throughout the circling

maneuver are distinctly visible using natural vision.

An EFVS cannot be used to satisfy the 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.

3. Enhanced Flight Visibility.

Flight visibility

is determined by using natural vision, and enhanced

flight visibility (EFV) is determined by using an

EFVS. 14 CFR part 91.175 (l) requires that the EFV

observed by using an EFVS cannot be less than the

visibility prescribed in the IAP to be used in order to

continue to descend below the DA or MDA.

b. EFVS Operations At or Below DA or MDA

Down to 100 Feet Above the TDZE.

The visual

segment of an IAP begins at DA or MDA and contin-

ues to the runway. There are two means of operating

in the visual segment−−one is by using natural vision

and the other is by using an EFVS. If the pilot determ-

ines that the EFV observed by using the EFVS is not

less than the minimum visibility prescribed in the IAP

being flown, and the pilot acquires the required visual

references prescribed in 14 CFR part 91.175 (l)(3) us-

ing the EFVS, then the pilot can continue the

approach to 100 feet above the TDZE. To continue

the approach, the pilot uses the EFVS image to visu-

ally acquire the runway environment (the approach