New Policy on 20:1 Visual Area Surfaces


On November 18, the FAA issued interim policy guidance regarding penetrations of the 20:1 visual area surface of instrument approach procedures. This guidance becomes effective on January 6, 2014. The FAA has noted that prior to January 6 action will not be taken regarding 20:1 penetrations unless the FAA has determined that the obstruction penetration is of sufficient concern to warrant immediate action.

Simultaneously, the FAA has asked the aviation standards organization RTCA to convene a 20:1 Task Group under the oversight of RTCA's Tactical Operations Committee.  The Task Group has been asked to provide recommendations regarding:

  • The sufficiency of time and clarity of expectations regarding airport operator verification of 20:1 surface penetrations
  • Improvements that can be made to compliance planning and obstacle mitigation processes
  • Actions that must be taken to mitigate risk associated with obstacle penetrations of the 20:1 surface, specifically increases to visibility minimums and/or night operations restrictions
  • Best mechanisms for communicating risk assessment and mitigation processes to key stakeholders, including airport operators

This task group is co-chaired Chris Oswald from ACI-NA and Chris Baum from the Air Line Pilots Association (ALPA).  The task group is composed of representatives from the airline, pilot, general aviation, and airport community. Airport representatives include Mike Hines from the Metropolitan Washington Airports Authority, Scott McMahon from Morristown Municipal Airport, Jeremy Worrall from the State of Alaska, and Justin Towles from AAAE.

The FAA "highly recommends Airport Sponsors take a proactive approach by reviewing all approach surfaces in advance of any flight check schedule to ensure they are clear, including any planned approaches depicted on the Airport Layout Plan (ALP)," noting that, "if an airport is part of a [FAA] review that uncovers obstacle penetrations, there is a limited amount of time to act before procedures are impacted." 

To get a general sense of when your airport's procedures are scheduled for review, the FAA has published its procedure review schedule here. Although the schedule is does not specifically note when the FAA will begin its reviews, they typically commence 30 to 60 days prior to the "Due Date" listed in the table. This list is updated on a regular basis and ACI-NA has requested that the FAA provide a sortable, searchable version for airport operator use.

We are interested in receiving member comments regarding the interim policy. Please contact Chris Oswald with any comments or questions. ACI-NA is also working with the FAA and AAAE to organize an industry webinar regarding the interim policy. We will provide information about this webinar in a subsequent committee notice.


The 20:1 visual area surface is described in Section 3.3.2.c of FAA Order 8260.3B, United States Standard for Terminal Instrument Procedures (TERPS).  The figure below depicts the "straight-in" configuration of the surface, which is aligned with and centered on the runway centerline. It has vertical slope of 20:1, beginning from the runway's threshold elevation. The surface begins 200 feet prior to the runway threshold and extends until reaching the decision altitude of the approach procedure it serves.

Straight-in Visual Area Surface

Visual Surface Area Graphic

Note: ½W=(0.138×d)+k         Source: FAA Order 8260.3B

For approach procedures applicable to Approach Category A and B aircraft (generally lower performance prop and turboprop aircraft), the initial half-width of the surface, "k", is 200 feet; for approach procedures applicable to Approach Category C & D aircraft (high performance turboprop and turbojet aircraft), the initial half-width is 400 feet. Different dimensional standards are applicable to visual area surfaces serving offset and circling approach procedures. Please consult TERPS for additional details.

The purpose of the surface is to protect aircraft during the last stages of approach procedures when pilots transition from instruments to visual guidance. Objects penetrating the surface must be lowered or lit to ensure pilots of approaching aircraft can see them. If they cannot be, the visibility minimums associated with the approach may need to be increased or nighttime use of the procedure may be disallowed.

Please note that the visual area surface is not independently defined in FAA Office of Airports Advisory Circular (AC) 150/5300-13A, Airport Design. The AC includes a composite threshold siting surface composed of multiple TERPS surfaces, including the 20:1 surface.  Although it is advisable for airport operators to review these threshold siting surfaces as well, the current FAA policy guidance only pertains to the 20:1 visual area surface.

Although visual area surfaces have been defined in TERPS for many years, the FAA began reviewing these surfaces more systematically earlier this year. Initially, the FAA would take immediate action—raising visibility minimums and/or disallowing night operations—via NOTAMs to address obstacle penetrations that were identified.  Unfortunately, several affected airport operators found that the obstacle data FAA used to make its determinations were erroneous (e.g., obstacles that had already been removed, obstacles that were depicted in incorrect locations). Other airports express concern that there was limited advance and post-NOTAM coordination between the airport and the FAA regarding 20:1 penetrations.

In response to these and other concerns from airport operators, the FAA developed established interim policy guidance to address penetrations of the 20:1 Visual Area Surface of instrument approach procedures. The interim policy incorporates a validation step during which airport operators can address erroneous obstacle data before NOTAMs are issued and provides a risk-based framework to address obstacle mitigation actions and timeframes. The interim guidance was issued on November 15, 2013, and will become effective on January 6, 2014.


ACI-NA is requesting comments from member airports and World Business Partners/Associate Members (WBPs/AMs) regarding the FAA's Interim Policy Guidance. ACI-NA will also be actively participating in the aforementioned RTCA Task Group. Finally, ACI-NA is working with our colleagues at FAA and AAAE to schedule webinar(s) for interested member airports and WBPs/AMs).


Please contact Chris Oswald if you have questions, comments, or need additional information regarding this topic.


This message has been distributed to the members of the Operations & Technical Affairs and Small Airports committees.