Improved Approaches and Low-Visibility Operations outlines ways to increase access and flexibility for approach operations through a combination of procedural changes, improved aircraft capabilities and improved precision approach guidance.
Phases of Flight
Timeline for Achieving OIs and Capabilities
1 Dependent on system acceptance by Houston Airport System.
2 LPV Approaches has moved to Performance Based Navigation portfolio, name changed to RNAV (GPS) Approaches.
3 Dependent on input from industry.
Selected Work Activities
1 OI 107107: Ground Based Augmentation System (GBAS) Precision Approaches (2013-2018)
- Supported by NextGen Flexible Terminal Environment
- Completed: Declared GBAS Cat I system operationally available at
- Declare GBAS Cat I System operationally available at
3 OI 107117: Low-Visibility/Ceiling Approach Operations (2010-2015)
- Supported by Operations Appropriations
- Completed: Completed NPRM for Enhanced Flight Vision System (EFVS) to 100 feet
- Publish NPRM for EFVS to 100 feet
- Disposition public comments from NPRM for EFVS to 100 feet
- Begin drafting final rule for EFVS to 100 feet
4 OI 107118: Low-Visibility/Ceiling Landing Operations (2015-2018)
- Supported by Operations Appropriations
- Completed: Completed NPRM for EFVS to touch down
- Publish NPRM for EFVS to touch down
- Disposition public comments from NPRM for EFVS to touch down
- Begin drafting final rule for EFVS to touch down
Descriptions of OIs and Capabilities
at least one site
GBAS Category I Non-Federal System Approval
GBAS provides local corrections to GPS to improve accuracy, integrity, and availability of the navigation service. GBAS is designed and being implemented to enable GBAS Landing System precision instrument approaches to Category (Cat) I, and eventually Cat II/III, minima for multiple runways. This includes runways not served by Instrument Landing Systems (ILS). The GBAS systems design for Cat I use in the National Airspace System was approved in 2009 and will serve as an incremental step toward the development of a Cat III approach. GBAS Cat I is being implemented as a non-federal system on a per-airport request basis. The GBAS Cat I increment involves government-industry partnerships and is anticipated to result in service provision at the first airport in 2012.
GBAS Category II/III Standards
GBAS is intended to provide precision approach service to Cat II/III minima without the need for critical area protection, and offer the potential for increased flexibility in approach design and highly accurate approach guidance to the runway. Similar to GBAS Cat I, GBAS Cat II/III provides improved low-visibility access and increases operational efficiency and single- and multiple-runway capacity through the use of GBAS ground stations. The FAA plans to develop Cat II/III standards for ground and avionics equipment and publish procedures for each runway end receiving GBAS service. The standards for GBAS Cat II/III are being developed in harmony with International Civil Aviation Organization standards.
EFVS for Takeoff
EFVS for low-visibility takeoff operations and for authorization of increased operational benefit, beyond situational awareness and safety, for equipped users. Such authorization, if approved, would allow EFVS-equipped operators to use enhanced vision systems to meet takeoff visibility requirements, as well as depart from some runways with reduced infrastructure, e.g., no centerline lighting.
EFVS to 100 Feet
The ability to conduct an approach and land in low-visibility conditions depends largely on the type of approach and the aircraft's capability. Infrared sensor technology currently is used in EFVS to provide pilots with an enhanced visual image and allow them to see, in certain low-visibility conditions, the visual references necessary to continue descending below Decision Altitude/Decision Height (DA/DH) or Minimum Descent Altitude (MDA) on an instrument approach procedure. Under 14 CFR Part 91.175, the FAA already allows EFVS to be used in lieu of natural vision to descend below DA/DH or MDA down to 100 feet above the runway touchdown zone on an instrument approach procedure. In order to descend below 100 feet, however, the visual references must be identified using natural vision.
The FAA is engaged in rulemaking to enhance the benefits of having EFVS capability by allowing commercial operators to dispatch and begin instrument approaches in more low-visibility conditions than currently authorized.
SVS for Lower Than Standard Approach Minima Operations
The FAA is evaluating various concepts for allowing SVS technology to be used to conduct instrument approach procedures with lower-than-standard minima (Cat II, special authorization (SA) Cat I, SA Cat II) or in lieu of certain ground infrastructure.
EFVS to Touch Down
EFVS will allow improved access, with a greater assurance of landing without needing to execute a missed approach. The FAA continues to work with RTCA on concepts, standards and criteria to support the use of EFVS all the way to touchdown. The FAA also is engaged in rulemaking activity that would permit EFVS to be used to touchdown. Under specific visibility conditions, authorized users could utilize the enhanced visual image to touchdown, which will further increase access to runways in low-visibility conditions.