Air Traffic Bulletin

Issue 99-3 SUMMER 1999

Table of Contents: [Back]
Controlled Flight into Terrain (CFIT) Avoidance
Upcoming Changes in ASOS Version 2.6
Warning Areas & Offshore Airspace

Controlled Flight into Terrain (CFIT) Avoidance

/*ET/ During the fall of 1997, the Commercial Aviation Safety Team, a combined organization of the Federal Aviation Administration (FAA), National Aeronautics and Space Administration, Air Line Pilots Association, Air Transport Association, and airplane and engine manufacturers dedicated to working together to improve aviation safety, chartered a team to look at CFIT accidents. The team developed strategies and interventions to minimize the occurrence of CFIT. The results were nine project areas; one of them is air traffic control.

The following provides a review of the current handbook paragraphs associated with assisting flight crews with situation awareness, safety alerts, minimum safe altitude alerts, and on-the-job training (OJT).

Facility managers need to emphasize the controller's responsibility to assist the flight crew in situation awareness. FAAO 7110.65, Para 2-1-6, Safety Alert, states: "Issue a safety alert to an aircraft if you are aware the aircraft is in a position/attitude which, in your judgement, places it in unsafe proximity to terrain, obstructions, or other aircraft. Once the pilot informs you action is being taken to resolve the situation, you may discontinue the issuance of further alerts. Do not assume that because someone else has responsibility for the aircraft that the unsafe situation has been observed and the safety alert issued; inform the appropriate controller."

Para 2-1-6a states: "Terrain/Obstruction Alert - Immediately issue/initiate an alert to an aircraft if you are aware the aircraft is at an altitude which, in your judgement, places it in unsafe proximity to terrain/obstructions. Issue the alert as follows:

(identification) LOW ALTITUDE ALERT,
THE (as appropriate) MEA/MVA/MOCA/MIA IN YOUR AREA IS (altitude), ..."

Para 5-1-10, Deviation Advisories, states: "Inform an aircraft when it is observed in a position and on a track which will obviously cause the aircraft to deviate from its protected airspace area. If necessary, assist the aircraft to return to the assigned protected airspace."

The issuance of a safety alert is a first priority. Recognition of situations of unsafe proximity may result from minimum safe altitude warning/E-MSAW/LAAS, Mode C, Conflict/Mode C, intruder alert, or pilot report. Once the alert is issued, it is solely the pilot's prerogative to determine what course of action, if any, will be taken.

With more aircraft equipped with flight management systems, we need to use all available tools to establish aircraft position. Do not fixate on just distance measuring equipment (DME). FAAO 7110.65, Para 2-5-3, NAVAID Fixes, states: "Describe fixes determined by reference to a radial/localizer/azimuth and distance from a very high frequency onmidirectional range (VOR)-DME/VOR collocated with tactical air navigation (TACAN)/TACAN/Instrument Lan-ding System (ILS)-DME or Microwave Landing System (MLS) as follows:

a. When a fix is not named, state the name of the navigational aid followed by a specified radial/localizer/azimuth and state the distance in miles followed by the phrase 'mile fix.'

b. When a fix is charted on a standard instrument departure, standard terminal arrival route, en route chart, or approach plate, state the name of the fix.

c. Use specific terms to describe a fix. Do not use expressions such as 'passing Victor Twelve' or 'passing J Eleven.' "

During the process of reviewing accident data, the need for stabilized vertical guidance approaches became evident. When available and practical, clear aircraft for approaches with vertical guidance (ILS). FAAO 7110.65, Para 4-8-1, Approach Clearance, states: "Clear aircraft for 'standard' or 'special' instrument approach procedures only." Paragraph 4-8-1 goes on to state, "An aircraft conducting an ILS/MLS approach when the glideslope/glidepath is reported out of service shall be advised at the time an approach clearance is issued. Standard Instrument Approach Procedures shall commence at an Initial Approach Fix, or an Intermediate Approach Fix if there is not an Initial Approach Fix. Where adequate radar coverage exists, radar facilities may vector aircraft to the final approach course in accordance with Para 5-9-1, Vectors to Final Approach Course."

Except for vectors for visual approaches, vector arriving aircraft to intercept the final approach course:

a. At least 2 miles outside of the approach gate unless one of the following exists:

1. When the reported ceiling is at least 500 feet above the MVA/MIA and the visibility is at least 3 miles, aircraft may be vectored closer than 2 miles outside of the approach gate but no closer than the final approach fix.

2. If specifically requested by the pilot, aircraft may be vectored to intercept the final approach course inside the approach gate but no closer than the final approach fix.

b. For a precision approach, at an altitude not above the glideslope/glidepath or below the minimum glideslope intercept altitude specified on the APC.

c. For a non-precision approach, at an altitude which will allow descent in accordance with the published procedure.

Para 5-9-4c. Approach clearance except when conducting a radar approach. Issue approach clearance only after the aircraft is:

1. Established on a segment of a published route or instrument approach procedure, or

2. Assigned an altitude to maintain until the aircraft is established on a segment of a published route or instrument approach procedure.


In some of the accidents reviewed, OJT was being conducted and may have contributed to the accidents. All OJT instructors are reminded to maintain control and vigilance on the position.

In some cases, non-rated controllers were operating a position unsupervised. FAAO 7220.1, Certification and Rating Procedures, Para 50b, states: "The individual may perform duties as a controller only at those sectors or positions at which they are qualified; otherwise, they are in training under the direct supervision of a controller qualified at the position being worked." (ATP-110)

Upcoming Changes in ASOS:Version 2.6

/*TFE/ This summer will mark significant changes in automated weather reporting. Beginning in August 1999, the National Weather Service (NWS) will start installing the ASOS Version 2.6 upgrade. There will be several new features with 2.6, but one of the most significant of these will be the ability of ASOS to report thunderstorm information in the body of the weather report.

The software upgrade will be implemented nationwide in stages. The level of priority will be influenced by several factors, such as the service level of the ASOS, geography, regional concerns, etc. Some of the criteria used in the service standards to rank the airports were based on (1) the occurrence of significant weather weighted by traffic counts; (2) the distance to the nearest suitable alternate airport; and (3) critical airport characteristics. These criteria produced a score for each airport that determined their level of service.

The four ASOS service levels and their responsible observers are as follows: Service Level A has NWS observers, NWS contract weather observers, FAA air traffic control specialists at AFSS's, or FAA contract weather observers. Service Level B observers are the same as service Level A. Service Level C has air traffic controllers at FAA ATCT's, AFSS's, and federal contract towers as observers. Service Level D locations are "stand-alone" sites and have no observer interface. The ASOS Operations and Monitoring Center (AOMC) has access to the entire system at all levels for remote maintenance and diagnostics.

In our ongoing effort to elevate the ASOS level of service to further emulate human capabilities, the first installations will occur at the stand-alone (Service Level D) sites. The changes that affect most users of the system are:

1. Thunderstorm Reporting

Presently, some NWS ASOS's have single-point sensors that provide thunderstorm information (cloud-to-ground and cloud-to-cloud lightning reports) at stand-alone sites, but only out to 10 miles. At FAA ASOS sites, the Automated Lightning Detection and Reporting system (ALDARS) will be interfaced when Version 2.6 is installed. This system will provide thunderstorm information (cloud-to-ground lightning reports) out to 10 miles of the airport and lightning information from 10 to 30 miles of the airport.

Thunderstorm activity will be reported as "TS" in the present weather field of the Metar/Speci if the report of the storm is located within a 5-mile radius of the airport. If activity is detected beyond 5 miles, but less than 10 miles from the airport, the thunderstorm is considered to be located in the vicinity of the airport and is reported as "VCTS." Any activity from 10 to 30 miles is defined as distant lightning and reported as "LTG DSNT (direction)." Unlike "TS" and "VCTS," "LTG DSNT NW" is reported in the remarks section of the weather report.

A SPECI will be generated when the thunderstorm activity indicates movement from outside of a 10-mile radius of the airport to inside the 10-mile ring and vice versa. Also, a SPECI will be generated when a previously reported thunderstorm has ended or has moved outside of 10 miles of the airport. A new SPECI criteria that will provide information on thunderstorm movement from 5 to 10 miles to within a 5-mile radius and vice versa is presently under review.

If there is no lightning detected for 15 minutes, a SPECI will be generated to end the storm with thunderstorm information in remarks. For example, TSE23 means the thunderstorm ended at 23 minutes after the hour. If lightning is present, but has moved outside of 10 miles, LTG DSNT NE TSE23 will appear in the remarks.

2. "PL"

The ice pellet designator has changed from "PE" to "PL." On November 5, 1998, an official change was made to the METAR report and was incorporated in the ASOS Versions 2.49 and succeeding versions. However, it continues to be classified as a new feature because there were ASOS sites that were commissioned with software Version 2.4 and did not receive this upgrade.

3. Missing Temperature/Dewpoints

Presently, the temperature and dewpoint report processing controls are combined, which has contributed to excessive temperature outages. Version 2.6 separates the controls, which will allow the observer to disable the dewpoint sensor, leaving the ambient temperature operational. In addition, the system will cease reporting dewpoint when the ambient temperatures are below minus 30 ºF.

4. Reduction of False Rain Reports

An interim blowing snow algorithm was added to reduce the number of false rain reports at 0 ºC and below.

5. Voicing Capability

There will be a change to the ASOS automated voice broadcast to support new visibility values and present weather parameters, such as thunderstorms. However, the automated voicing dictionary for the Digital ATIS (D-ATIS) will require some editing at the facility level to accommodate the new entries.

Upon receipt of the ASOS Version 2.6 CBI, each facility equipped with D-ATIS shall ensure that the automated voice dictionary supports the new weather contractions necessary for thunderstorm reporting. A national software upgrade is presently being developed for D-ATIS which will include the changes but may not be available prior to Version 2.6 installation. An example of some of the upcoming changes are: VCTS (voiced as, "thunderstorm in the vicinity"); TSB (voiced as, "thunderstorm began at"); TSE ( voiced as, "thunderstorm ended at"); and DSNT (voiced as, "distant").

ATCT's that edit the remarks field of the METAR/SPECI report prior to broadcasting the D-ATIS shall ensure that thunderstorm/lightning information is included (FAAO 7110.65, Para 2-9-3a).

In addition to the features above, the following are changes that affect air traffic controllers:

1. Visibility

When the visibility decreases to a value less than ¼ mile, the visibility can now be augmented to the following values: 1/8, 1/16, or 0.

2. RVR

Runway Visual Range data can be entered manually or interfaced (if configured) through the New Generation RVR. The observer will be able to edit RVR information in the body of the report on the OID.

3. System Alerts

The observer will be prompted on the OID when thunderstorm, precipitation identifier, and freezing rain data are unavailable and when restored.

When a controller is signed on as "OBSERVER," three messages will be displayed in yellow on the lower left corner of the one-minute screen that describe the status of thunderstorm (TSTM), precipitation identifier (PRECIP IDENT), and freezing rain (ZR) data. If the system is operating normally, a steady message will display TSTM DATA AVAILABLE. If thunderstorm data becomes unavailable, the message will flash TSTM DATA N/A for one minute and change to steady. Then when the information is restored, the message will flash TSTM DATA AVAILABLE for one minute and return to steady. A separate message will display "PRECIP IDENT" and "ZR" information in the same manner.

When an individual is signed on as "CONTROLLER," the one-minute screen will display thunderstorm data only, as described above.

4. 7900.5 Compliance

Version 2.6 will fully implement present weather encoding rules for METAR. The reporting of present weather will be modified to comply with FAAO 7900.5, Surface Weather Observing - METAR Handbook format. For example, the automated voicing will change from "Ground Fog " to "Shallow Fog." This updates the old Surface Aviation Observation (SAO) terminology to the correct METAR terminology.




Warning Areas and Offshore Airspace

/*E/ In February 1997, an Air National Guard F-16, operating in warning area airspace over the Atlantic Ocean, intercepted a Nations Air Boeing 727 (B-727) that was traversing the warning area on an IFR flight plan. The proximity of the F-16 activated the B-727's Traffic Alert and Collision Avoidance System (TCAS), requiring the B-727's flight crew to execute several maneuvers in response to the TCAS Resolution Advisories.

The National Transportation Safety Board investigated this incident and identified concerns in the areas of communications, coordination procedures, and responsibilities for the separation of aircraft transiting warning areas.

The FAA and the DOD also investigated the incident and conducted a joint review of procedures to determine if there is a need for additional guidance on the joint use of warning areas. The review found that existing letters of agreement (LOA) or memoranda of understanding (MOU) provide adequate guidance and procedures for the activation, deactivation, and joint use of warning areas, and that these procedures, when properly adhered to, are satisfactory. The FAA/DOD review group noted, however, that some confusion exists over the classification of offshore airspace, the status of warning areas, and the operating rules and separation standards that apply when nonparticipating aircraft transit a warning area.


International Civil Aviation Organization (ICAO)

ICAO is an agency of the United Nations that originated from the signing of the Convention on International Civil Aviation in December 1944 (referred to as the Chicago Convention). This organization was formed to promote the safe and orderly development of international civil aviation. The Chicago Convention produced International Standards and Recommended Practices (SARP) aimed at standardizing international civil aviation operational practices and services. Currently, these SARP's are contained in 18 annexes to the Chicago Convention. In particular, Annex 2, Rules of the Air, and Annex 11, Air Traffic Services, are pertinent to this paper as they relate to civil aircraft operations, the establishment of airspace, and air traffic control (ATC) services in international airspace. Although not addressed in this paper, it should be noted that the SARP's are augmented by various ICAO documents containing Procedures for Air Navigation Services (PANS) that amplify the basic principles in the SARP's. Further, to supplement the worldwide procedures contained in the annexes and PANS, ICAO develops Regional Supplementary Procedures, which are part of the Air Navigation Plans agreed upon to meet the needs of specific geographical areas.

Two articles of the Chicago Convention also have a bearing on the subject of this paper:

Article 3:

Exempts state-owned aircraft (which includes military aircraft) from the provisions of Annex 11 and its Standards and Recommended Practices. (Note: As an ICAO Contracting State, the U.S. has agreed that its state aircraft will be operated in international airspace with due regard for the safety of civil aircraft.)

Article 12:

Obligates each ICAO Contracting State to adopt measures to insure that persons operating an aircraft within its territory shall comply with that state's air traffic rules; or with Annex 2, Rules of the Air, when operating over the high seas. The U.S. satisfied this responsibility through Title 14, Code of Federal Regulations (CFR) Part 91 which requires that operators of aircraft comply with U.S. operating rules when in the U.S., and that U.S.-registered aircraft comply with Annex 2 when over the high seas (see section 91.703). However, section 91.703 applies only to civil aircraft, and state aircraft operating outside the U.S. are only subject to the "due regard" provisions of Article 3 of the Convention.

Under ICAO agreements, the SARP's in Annex 11 apply to airspace under the jurisdiction of a contracting state which has accepted the responsibility of providing air traffic services over the high seas, or in airspace of undetermined sovereignty.

ATC Services

The U.S. has accepted responsibility for providing oceanic air traffic control services within Flight Information Regions (FIR) in a portion of the western half of the North Atlantic, most of the Gulf of Mexico, and a large portion of the North Pacific. Within these Control Area (CTA)/FIR's, the U.S. applies oceanic separation procedures consistent with ICAO regional procedures. These procedures are contained in FAAO 7110.65, Chapter 8, Oceanic/Offshore Procedures.

The FAA applies domestic ATC procedures within airspace over the U.S. and adjacent waters out to the 12 NM limit. In accordance with Annex 11, the FAA may also apply domestic ATC procedures within designated offshore controlled airspace (within areas of domestic radio navigational signal or ATC radar coverage) from the 12 NM limit outward to the inner (i.e., closest to the U.S.) CTA/FIR boundaries. ICAO agreements permit the application of domestic ATC procedures even though this is international airspace. (Note: Either domestic or ICAO procedures could be used in offshore controlled airspace depending on the extent of navigational signal or radar coverage in the area.)

U.S. Domestic Airspace Limit

Until December 1988, the U.S. territorial limit was set at 3 NM from the coast of the United States. On December 27, 1988, President Ronald Reagan signed Proclamation No. 5928 which extended the territorial sea of the United States out to 12 NM from the coast.

To accommodate the territorial extension, the FAA amended 14 CFR Parts 71 and 91 to extend controlled airspace (Class E and Class A), and the applicability of certain flight rules, to include the airspace overlying the waters between 3 and 12 NM from the U.S. coast. This FAA action was necessary for the U.S. to extend its domestic air traffic control authority and procedures over airspace that is no longer considered a part of the high seas; and to require operators to comply with FAA flight rules rather than ICAO Rules of the Air in that airspace.

The presidential proclamation also had an immediate impact on the status of a number of existing warning areas that were established based on the former 3 NM territorial limit. This warning area issue will be discussed later in this paper.

U.S. Domestic Airspace Classification

In 1993, the FAA reclassified U.S. airspace by adopting the airspace classes recommended by ICAO. Probably the most familiar feature of the airspace reclassification is the replacement of "old" terms such as "Positive Control Area," "Terminal Control Area," "Control Zone," etc., with ICAO letter classifications (Class A, B, C, D, etc.).

Offshore Airspace

Also in 1993, the FAA issued the "Offshore Airspace Reconfiguration" rule which supplemented the domestic airspace reclassification effort. In part, the Offshore rule redesignated certain "additional control areas," over international waters, as "Offshore Airspace Areas." This part of the rule provided for the designation of Class A or Class E airspace, in international airspace, within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic ATC procedures are applied.

According to FAAO 7400.2D, Procedures for Handling Airspace Matters, Offshore Airspace Areas are designated between the U.S. 12 NM territorial limit and the oceanic CTA/FIR boundary. There has been some confusion over whether this meant the CTA/FIR boundary closest to, or farthest from, the U.S. The correct interpretation is that Offshore Airspace Areas extend out to the CTA/FIR boundary closest to the U.S. in order to facilitate the use of domestic procedures. Within the CTA/FIR area itself, ICAO oceanic ATC procedures are used instead of domestic procedures.

As mentioned above, Offshore Airspace Areas are still international airspace, but under ICAO agreements, the FAA may apply domestic ATC separation procedures in those areas. It is important to reiterate that state aircraft are subject only to the "due regard" provisions of the Chicago Convention when operating beyond 12 NM from the U.S. coast.

DOD Policies Regarding Operations in International Airspace

Military aircraft are considered to be "state" aircraft and, as such, the DOD may elect to conduct certain operations in international airspace under "due regard" instead of ICAO flight procedures.

DOD policies regarding the use of ICAO procedures and military operations over the high seas are stated in DOD Flight Information Publication (FLIP), General Planning, Chapter 6, International Civil Aviation Organization; and Chapter 7, Operations and Firings Over the High Seas. These policies are summarized in the following excerpts from the FLIP, General Planning:

- The airspace beyond the territorial sea is considered international airspace where the permission of the coastal state is not required for overflight or related military operations. Military aircraft operating in international airspace are not legally subject to the jurisdiction or control of air traffic control authorities of a foreign country.

- Although ICAO rules and procedures are binding upon civil aviation only, military aircraft are expected to avoid conflicting with national regulations. Normally, routine point-to-point and navigation flights shall follow ICAO flight procedures.

- It is the policy of the DOD that all United States military aircraft and firings shall operate with due regard for the safety of all air and surface traffic. When practical and compatible with the mission, U.S. military operations on the high seas shall observe ICAO flight procedures.

- Operations not conducted under ICAO flight procedures are conducted under the "Due Regard" or "operational" prerogative of military aircraft, subject to one or more ... conditions ... [which] ... provide for a level of safety equivalent to that normally given by ICAO ATC agencies. Flight under these provisions shall be regarded as deviations from normally accepted operating procedures and shall not be undertaken routinely.

For more information about pilot responsibilities when operating under "due regard," refer to the "Terms of Reference" section in FAAO 7110.65L, Chapter 1; or FLIP, General Planning.

Warning Areas

A warning area is one of the six types of special use airspace (SUA) areas. Warning areas contain activities that may be hazardous to nonparticipating aircraft. These areas may contain a wide variety of aircraft and non-aircraft activities, such as: aerial gunnery, bombing, aircraft carrier operations, surface and subsurface operations, naval gunfire, missiles, etc. Although warning areas may contain hazards similar to those found in a restricted area, the U.S. does not have the authority to prohibit flight by nonparticipating aircraft in international airspace. Therefore, warning areas are designated to alert nonparticipating aircraft to the potential danger.

To more fully understand the current status of warning areas, it is necessary to review the changes that have occurred since 1988.

Originally, warning areas were only designated over international waters, (beyond the former 3 NM limit). When the President extended the territorial sea out to 12 NM, the airspace between 3 and 12 NM from the coast was no longer considered international airspace. This immediately caused many existing warning areas to lie partly within domestic airspace instead of being located totally within international airspace, as called for by the warning area establishment criteria. The issue was further complicated by the FAA's extension of controlled airspace (Class E and Class A), and Part 91 operating rules out to 12 NM, because this would have prohibited the DOD from conducting hazardous activities in that 3 to 12 NM segment without either an exemption to the regulations, or the designation of another type of SUA. This situation would have adversely impacted military training and/or prevented access by nonparticipating aircraft to airspace where they have freely operated for years.

To allow the continuation of ongoing military activity in the existing warning area segments between 3 and 12 NM, and to preserve the right of nonparticipating aircraft to fly through these areas, the FAA issued Special Federal Aviation Regulation No. 53 (SFAR 53).

SFAR 53 established regulatory warning areas between 3 and 12 NM from the coast. The SFAR used the terms "warning area" to identify these regulatory warning areas, and "nonregulatory warning area" to indicate those areas beyond 12 NM, located entirely over international waters.

SFAR 53 specifically stated that Part 91, Subpart B, applies within the regulatory warning areas. However, the SFAR further stipulated that pilots of participating aircraft, operating in a warning area with the approval of the using agency, may deviate from the rules of Part 91, Subpart B, to the extent that the rules are not compatible with the mission. Nonregulatory warning areas were not affected by the SFAR.

The SFAR was intended to be an interim measure with the sole purpose of enabling the continuation of military training activity, and maintaining the right of nonparticipating aircraft to fly through those portions of warning areas located between 3 and 12 NM from the coast, while a permanent solution was developed.

After the presidential proclamation was issued, the DOD adjusted the boundaries of numerous warning areas outward to 12 NM. However, DOD requirements called for certain warning areas to remain at 3 NM. The FAA then, faced the dilemma of how to accommodate DOD's requirements between 3 and 12 NM from the coast without taking action that would impose an undue burden on nonparticipating aircraft (e.g., fish spotters, etc.) which had flown in the 3 to 12 NM offshore portion of warning areas for decades.

Following considerable study of this issue, the FAA decided that the best solution was to adopt a new definition of warning areas that incorporated the provisions of SFAR 53 and combined the SFAR 53 definitions in a single term. The FAA implemented this decision by issuing the "Definitions of Special Use Airspace" rule which codified all SUA definitions, including warning areas, and incorporated them into 14 CFR Part 1. This rule consolidated the SFAR 53 definitions of "warning area" and "nonregulatory warning area," into a single term that applies in both domestic airspace (located between 3 and 12 NM from the U.S. coast), as well as international airspace, beyond the 12 NM limit. The FAA determined that the combined definition is appropriate since the procedures that apply to the two warning areas are the same. This new definition, which became effective when SFAR 53 expired on January 15, 1996, reads as follows:

"Warning area: A warning area is airspace of defined dimensions, extending from 3 nautical miles outward from the coast of the United States, that contains activity that may be hazardous to nonparticipating aircraft. The purpose of such warning areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both."

The effect of this change is that existing warning areas may continue to be located in domestic airspace, beginning 3 NM from the U.S. coast. The DOD may continue to conduct hazardous activities there, and nonparticipating pilots are warned about the presence of hazards, but are not prevented from entering the area. Furthermore, Part 91, Subpart B, does apply in that portion of warning areas between 3 and 12 NM from the coast; but, when the warning area is active, participating pilots may deviate from the rules to the extent that they are not compatible with the mission.


Joint Use of Warning Areas

It is FAA policy that all SUA, including warning areas, should be made available for use by nonparticipating aircraft when all or part of the airspace is not needed by the using agency, provided there is no derogation to the using agency's mission.

Notwithstanding the above, the FAA will not route nonparticipating IFR aircraft through an active warning area unless provided for in a LOA. Otherwise, FAA will clear nonparticipating aircraft via routing which will provide approved separation from the airspace.

To initiate joint use of a warning area, an LOA is executed between the controlling agency and the using agency. These LOA's are prepared on a site-specific basis in order to accommodate the unique circumstances of each particular location. The LOA provides for the activation and deactivation of the warning area and defines the conditions under which nonparticipating aircraft may be authorized to operate within or through the area. The incident described at the beginning of this article highlights the importance of the LOA in ensuring the efficiency and safety of joint use of warning areas, It is most important that the LOA clearly define the conditions, the procedures, and the separation to be applied when a nonparticipating aircraft is transiting the area.


So what, then, does all this mean for daily operations? A number of questions have been asked regarding the status of warning areas and the operating rules that apply to them.

We have seen that warning areas may now exist over both domestic and international waters. The rules that apply to warning areas depend on whether the area lies within domestic or international airspace. Class A and Class E airspace and Part 91 flight rules apply within warning area airspace located between 3 and 12 NM from the coast. However, a military pilot operating in an active warning area in this segment may deviate from Part 91 to the extent that the rules are not compatible with the mission. Section 91.703 incorporates international operating rules for aircraft operations conducted beyond 12 NM from the coast. But, those operating rules only apply to civil aircraft. In a warning area (or other airspace) outside of 12 NM from the coast, military pilots are only subject to the "due regard" provisions of Article 3 of the Chicago Convention.

Thus, may a military pilot operate VFR, above FL 180, in an active warning area within 12 NM from the coast? The answer is "Yes," if mission requirements dictate. Would this violate the requirements for operating in Class A airspace? Answer: "No," again, because the pilot may deviate from the rules if they are incompatible with the mission.

This, then, leads to the question of what separation standards apply to a nonparticipating aircraft while it is transiting a warning area (regardless of whether transit occurs in a segment of the warning area that is within or outside the 12 NM limit). Keeping in mind that the pilot of a participating aircraft operating in a warning area may deviate from Part 91 rules and/or operate under "due regard," as appropriate, the LOA that governs joint use of a warning area becomes a critical element in ensuring a safe operation.

Ordinarily, military activities in an active warning area could be expected to occur without restraint. However, where joint use is agreed to by the FAA and DOD, it may be necessary for the LOA to include provisions for ATC to temporarily impose some restrictions on those activities so that joint use transit of an active warning area can be conducted safely. The methods for achieving this are agreed to by the using and controlling agencies and incorporated into the LOA.

Whenever a nonparticipating IFR aircraft is transiting an active warning area under joint use procedures, it should be afforded approved domestic IFR separation, in accordance with FAAO 7110.65, from all participating aircraft. The using and controlling agencies should include in the LOA whatever provisions are necessary to accomplish this. For example, the LOA could provide for:

- The controlling agency to issue restrictions to the military aircraft that will ensure approved IFR separation is maintained from the nonparticipating traffic.

- The creation of lateral and/or vertical internal subdivisions of the area to facilitate joint use and provide the required separation from warning area activities.

In any case, the LOA should leave no gray areas as to the procedures, conditions, and the separation standards that will be applied while a nonparticipant is in the warning area. Whenever the using agency's mission requirements or other circumstances preclude compliance with the LOA procedures, joint use, obviously, must be terminated until such time as the agreed-upon procedures can be met.

(Note: The above discussion applies to activities conducted in warning areas. In the case of military operations conducted in airspace that is both beyond the 12 NM limit and outside a designated warning area, there are no "joint use" LOA's covering those operations, and the military activity is subject solely to "due regard" provisions.)


Positive action in applying warning area joint use procedures should prevent a recurrence of incidents such as the one described above. Real time joint use of warning areas has been conducted safely for many years. A clear, specific LOA, combined with thorough knowledge of LOA requirements by all concerned, will ensure that joint use remains an effective and safe air traffic management tool.


1. FAA Order 7400.2D, "Procedures for Handling Airspace Matters."

2. FAA Order 7400.9F, "Airspace Designations and Reporting Points."

3. FAA Order 7110.65L, "Air Traffic Control."

4. FAA Order 7610.4.1, "Special Military Operations."

5. DOD Flight Information Publication (FLIP), General Planning, Chapter 6, "International Civil Aviation Organization," and Chapter 7, "Operations and Filings Over the High Seas."

6. Executive Order 10854, "Extension of the Application of the Federal Aviation Act of 1958," November 27, 1959.

7. Advance Notice of Proposed Rulemaking, "Controlled Airspace Designations in International Airspace" (50 FR 30798), July 29, 1985.

8. Presidential Proclamation No. 5928, "Territorial Sea of the United States," December 27, 1988.

9. Final Rule, "Applicability of Federal Aviation Regulations in Airspace Overlying the Waters Between 3 and 12 Nautical Miles from the United States Coast (54 FR 264), January 4, 1989.

10. Special Federal Aviation Regulation (SFAR) No. 53, "Establishment of Warning Areas in the Airspace Overlying the Waters Between 3 and 12 Nautical Miles from the United States Coast" January 4, 1989.

11. Final Rule, "Airspace Reclassification," (56 FR 65638), December 17, 1991.

12. Final Rule, "Offshore Airspace Reconfiguration," (58 FR 12128), March 2. 1993.

13. Final Rule, "Definitions of Special Use Airspace," (61 FR 2080), January 24, 1996.

14. Title 14, Code of Federal Regulations (CFR), parts 1, 71, and 91.

15. Annex I I to the Convention on International Civil Aviation, International Standards and Recommended Practices, Air Traffic Services. (ATA-400/ATP-130)



Hey! Did you know that we are still having operational errors and deviations out there? I guess that is really no big surprise for most of us. The demands of the job are such that the system is still vulnerable to human error. For the most part, good backup systems and procedures are in place to act as a "safety net" to prevent human failings from causing disastrous incidents. But errors continue to plague us and, sadly, most of them are preventable. Some errors may be prevented simply by professionalism, that is, the quality of self-discipline that ensures that the details of the job are met. Some people contend that they are just too busy to attend to the details of phraseology and procedure. In some cases, that sense of being too busy is a faulty perception. In other cases, they really are busy, but are not effective in managing the situation. Here is an example that I have heard more than several times. (As Dave Barry says, "I swear I am not making this up!")

The frequency was not busy, in fact, it was very quiet. The controller made several transmissions, and then said something close to, "All right everyone, listen up! I'm really busy and you're stepping all over each other and I don't have time for this!" There had been no telltale interference to alert the crew that a transmission had been blocked. So what was the controller getting all in a lather about?

The controller was transmitting and receiving on several different frequencies at the same time. When one crew waited until the controller was finished speaking before beginning their transmission, two other crews were doing the same thing. The result was that the controller heard three crews stepping on each other. A good crew will listen to the frequency to be sure that no one else is transmitting at the time before beginning their transmission. This is standard operating practice as well as decent manners. The problem cannot be remedied, however, when the controller is transmitting and receiving on multiple frequencies simultaneously, because aircrews on different frequencies cannot know when the other frequency is being used. The result is blocked transmissions for the controller. Blocked transmissions can increase a controller's workload exponentially.

During midshifts and in sectors that are geographically very large, the use of multiple frequencies may be a fact of life. However, every effort should be made to avoid this scenario as much as is operationally possible. When it happens that multiple frequency problems are getting the controller frustrated, telling the pilots that THEY have to pay more attention is silly and insulting, because they are not the problem and they cannot help. The problem is us!

Blocked frequencies could contribute to a scenario where an error may occur. Here are some other ways that folks got themselves into a trap that resulted in an error or deviation.

Lately, we have seen several instances of "Inefficient Efficiency," where the controller coordinated with an adjacent sector/position/facility for an aircraft altitude change ahead of time. The ATCS marked the altitude change on the flight progress strip, entered the data into the flight data block…and then forgot to issue the clearance to the pilot! The aircraft crossed into the adjacent airspace still at an interim altitude assignment. Perhaps the controller just got ahead of him/herself.

The "Why-Not-Put-Off-Now-What-I-Can-Prob-ably-Do-Later" trap. Also known as procrastination or dithering, it happens when the ATCS recognizes that a conflict is developing between aircraft 200+ miles apart. Instead of taking action immediately in the form of a 10-degree heading correction, routing or altitude change, the ATCS puts the chore off. Typically, when the aircraft are approximately 10 miles apart, the ATCS will issue a 10-degree course correction. Alas, this is far too little, too late, and separation is lost.

The "I-Thought-You-Knew-What-I-Wasn't-Thinking-About" trap. Some folks get caught in the trap of assuming that the other person is aware of a developing conflict. Here is a typical instance that illustrates the lack of communication between controllers. ATCS A requested controller B to assign an aircraft 6,000 feet and A agreed. Before the aircraft was switched to controller A's frequency, controller B handed off an aircraft to controller A descending to 6,000 feet. Controller B immediately saw the conflict but did not say anything to controller A because it was assumed that controller A remembered the climbing aircraft and would ensure that separation was maintained. Unfortunately, controller A did not take action and separation was lost. The moral of the story is that controllers should always agree to double check apparent aeronautical oddities. (AAT-200)


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