Air Traffic Bulletin

Issue 99-5 FALL 1999

Table of Contents: [Back]
Approved Alimeter Setting for Instrument Approach
Priority of Weather Dissemination
Canceling Takeoff Clearances
Runway Exiting or Taxi Instructions
Use of AWOS at FAA Towered Airports
Compassion Flights
Land and Hold Short Operations (LAHSO) Clearance
Aeronautical Information Cutoff Schedule for the Year 2000

Approved Alimeter Setting for Instrument Approach

/*TE/ Air Traffic is aware of occurrences of controllers issuing unauthorized altimeter settings for aircraft on instrument approaches. FAAO 7110.65, Air Traffic Control, Paragraph 2-7-2d, Altimeter Setting Issuance Below Lowest Usable FL, Note 1, states, "The destination altimeter setting, whether from a local or remote source, is the setting upon which the instrument approach is predicated."

Approach charts will specify the authorized source for the altimeter setting. If an airport has an automated weather system, such as the Automated Surface Observing System (ASOS) or Automated Weather Observation System (AWOS), it will be the primary source for the altimeter. If the automated system is inoperative and an approved backup system, such as a digital altimeter setting indicator, altimeter setting indicator, or mercurial barometer is not available for the airport, the instrument approach is not authorized unless an alternate altimeter setting is authorized by Flight Standards. Approach charts to remote nontowered airports specify the alternate altimeter source to be used for the approach. Approach minimums are authorized only for the approved altimeter source. In accordance with FAAO 7110.65, Paragraph 2-7-2a, "Identify the source of an altimeter setting when issued for a location other than the aircraft's departure or destination airport."

Whenever ASOS /AWOS is the primary source for the altimeter and is inoperative, the Flight Technologies and Procedures Division, AFS-400, has requested it be contacted at (405) 954-3027. It will contact the Flight Data Center to publish a notice to airmen for a backup altimeter source and corresponding minimums, or to render the approach unusable. (ATP-100)


Priority of Weather Dissemination

/*TF/ During a recent investigation of automated weather dissemination, a concern was raised regarding the priority of long-line weather dissemination as opposed to local dissemination.

When the ASOS automatically disseminates a weather observation via long-line transmission, the time of receipt by the user varies due to landline restrictions, but usually is from 3 to 10 minutes.

In accordance with FAAO 7900.5A, Surface Weather Observing - METAR, Paragraph 3-6, Dissemination Requirements, the controller/observer is required to give local dissemination to all weather reports. This paragraph states, "If reports cannot be disseminated simultaneously, local and long-line, they shall be disseminated first to the local airport traffic control users, then disseminated long-line."

If controllers operate in accordance with the above paragraph, the locally disseminated weather report will usually be received prior to the long-line disseminated report." (ATP-100)


Canceling Takeoff Clearances

/*T/ Several recent events have occurred where controllers have directed aircraft on a takeoff roll to abort the takeoff. While this is always an option, controllers are reminded to be aware of the following points from a pilot's perspective:

  • Cockpit workload is very high during the takeoff event.
  • It is possible that a pilot may not be able to comply with such a clearance once a certain speed has been attained.
  • Cockpit ambient noise, workload, or required intra-cockpit communications may preclude the pilots from hearing the clearance to abort.

Additionally, some of the possible consequences of an aborted takeoff may include:

  • Hot Brakes Delaying subsequent takeoffs, affecting future abort capability, and/or a brake fire.
  • Directional control problems due to asymmetric heavy brake application or reverse thrust application.
  • Overrunning the end of the runway because of the inability to stop in the remaining distance. An abort at high speed requires maximum stopping effort where everything must go exactly right.

Controllers are reminded that while an instruction to abort a takeoff or cancellation of a takeoff clearance is always an option, it should be issued with care, and not used routinely. (ATP-100)


Runway Exiting or Taxi Instructions

(This article originally appeared in Bulletin 98-3)

/* T/ Taxi instructions are something we are all familiar with and issue hundreds of times a day. Although there is no definition in the Pilot/Controller Glossary that defines "taxi instructions," taxi is the movement of an airplane under its own power on the surface of an airport.

Recent feedback from our users indicates we may have become complacent about when we issue taxi instructions, especially to landing aircraft during the critical phase of operation immediately after touchdown.

During the touchdown and deceleration of an aircraft, the workload in the cockpit is extremely high, as is the noise level. It is possible that a control instruction like, "Turn left at highspeed Tango, hold short of Runway 12 and contact ground on 121.7," may be misheard or misunderstood and result in a serious incident. Although it is impossible for any controller to know what is happening in the cockpit or to effectively assess what is a "critical phase" of the flight, every effort should be made not to issue instructions at this point in the flight.

Unless a duty of higher priority dictates, we should attempt to avoid issuing taxi instructions during critical operations such as immediately after landing. When to issue that instruction must rest with the judgment of the controller after considering factors which may include, but are not limited to, aircraft type, configuration, and speed, as well as the landing environment (including existing weather and runway conditions). These variables represent subjective observations and a controller is expected to use prudent judgment. (ATP-120)


Use of AWOS at FAA Towered Airports

/*TEF/ Operational FAA airport traffic control towers (ATCT) use hourly aviation routine weather reports (METAR) or, when criteria warrants, special (SPECI) observations to make decisions in providing air traffic service. Although the AWOS has the capability of reporting minute-by-minute observations, it is not acceptable for AWOS to broadcast minute-by-minute information to pilots while receiving control instructions from the controller who is using the METAR/SPECI information. A minute-by-minute weather report is disseminated locally and cannot be transmitted via long-line dissemination to other users such as the National Weather Service, Department of Defense, airline operations centers, flight service stations, and other FAA control facilities.

As stated in FAAO 7210.3, Facility Operation and Administration, Paragraph 2-8-2d, Receipt and Dissemination of Weather Observations, "AWOS towers with Limited Aviation Weather Reporting service certified controllers shall only use AWOS operator interface device information to generate a manual hourly METAR/SPECI observation." The dissemination of two different weather observations for the same airport is contrary to FAA policy and procedure. Pilots, air traffic controllers, and dispatchers use the official weather observation for flight planning, air traffic control decisions, conformance with FAA and airline procedures, and Code of Federal Regulations requirements.

When the ATCT is open and equipped with an Automatic Terminal Information Service (ATIS), ATIS shall be used to broadcast the current hourly or SPECI weather, and AWOS/ASOS will be inhibited. If ATIS is not available, the controller will provide current weather and airport information."

During the hours the ATCT is closed, AWOS shall be set to broadcast minute-by-minute observations. (ATP-100)


Compassion Flights

/*FTE/ Page 4 of the April 13, 1999, edition of the FAA INTERCOM featured an article called "CALLING ALL ANGELS." The text was as follows:

"It is now easier to identify angels in the air, thanks to the FAA. The agency has assigned a three-letter identifier code that can be used by pilots across the country flying as part of the Air Care Alliance, a group of non-profit charitable organizations that provide medical transport for patients.

The organization's 4,000 members including many FAA employees also provide transport for tissue/organ transplants and emergency/disaster relief roles.

The new three-letter identifier - CMF - and its telephony call sign "COMPASSION," make it easier for pilots to file flight plans with the FAA, reduce potential confusion about their mission, and provide a heads-up to air traffic controllers about the type of flight they will be handling.

Rol Murrow, former chairman of Air Care Alliance, explained that some Air Care Alliance flights in the past have been mistakenly identified as 'Lifeguard' flights, which receive priority handling by air traffic controllers because they involve life-and-death situations. Although some Alliance flights are flown under the 'Lifeguard' identification, it is usually not necessary.

Using the CMF identifier, however, does allow the Air Care Alliance pilots to request special handling to keep patients comfortable, such as flying at lower altitudes or on routes that avoid potential turbulence.

Angel Cases, an Airspace and Procedures specialist in the New England Region's Air Traffic Division, was one of the FAA leads in designating the new identifier code. Because of their mission to communities throughout the U.S., Cases expedited Air Care Alliance's request for an identifier code. 'I needed to make sure they met the requirements, and if they weren't able to, I wanted to assist them in documenting a case for a waiver to the requirements. That way they would be able to perform their mission,' Cases said.

Because of the FAA's work on this issue, volunteer pilot organizations like Angel Flight Northeast in Andover, Mass., Wings of Mercy in Muskegon, Mich., and Angel Flight West out of Santa Monica, Calif., can now provide their missions in a clearer, safer environment.

In addition to Cases, Murrow wanted to especially thank the Flight Services Division of Air Traffic Procedures (ATP-300) and all other FAA offices that helped with this effort. 'Air Care Alliance's mission has been supported steadfastly by officials and the rank and file of the FAA,' Murrow said."


"COMPASSION" flights are not "LIFEGUARD" flights. If an Alliance pilot wants priority handling, the flight plan must be changed to "LIFEGUARD."

CMF and "COMPASSION" identify the flight as non-profit, charitable, community service. It encompasses many facets of the Alliance (Mercy Mission, Angel Flight, Make-a-Wish, St. Jude's, etc.), and although there is no priority handling involved, minimal delay would be appreciated.

The Alliance may now file IFR flight plans under the CMF umbrella, which will give them better access to less turbulent altitudes and alternate routes. Controller suggestions in advance would be appreciated, as most of these organizations do not have access to sophisticated flight planning or weather networks.

Flight plans will be filed as CMF + digits (maximum 4) to identify the flight or aircraft, with "COMPASSION" in remarks. (ATP-300)


Land and Hold Short Operations (LAHSO) Clearance

(This article originally appeared in Bulletin 98-3)

/*T/ Air traffic controllers have been conducting Land and Hold Short Operations (LAHSO) since 1968. Until July 17, 1997, LAHSO was conducted to intersecting runways only and that procedure was referred to as Simultaneous Operations on Intersecting Runways (SOIR). Prior to July 17, 1997, there were a few locations that were authorized for landing and holding short of a taxiway or approach path.

Feedback from our users indicates that, occasionally, LAHSO clearances have been refused by the pilot and the refusal has been questioned by the controller. Please remember that the pilot is directly responsible for, and is the final authority concerning, the operation of an aircraft, and depending on several variables, may not be able to accept this type of clearance. FAA Notice 7110.199 clearly defines that when LAHSO are expected to be utilized, an announcement shall be made on the Automatic Terminal Information System or pilots shall be advised on initial contact or as soon as practicable thereafter to expect a LAHSO clearance.

If the requirements of the user or pilot prevent the acceptance of a LAHSO clearance, it is the responsibility of the pilot to inform ATC as soon as possible. (ATP-120)



Aeronautical Information Cutoff Schedule for the Year 2000

/*TEF/ Strict adherence to specified cutoff dates will ensure that aeronautical information is published on the desired effective date.

























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* Denotes Change Notice (CN). NOTE: There is no CN for Alaskan procedures.







For northern facilities personnel, 'tis the time of year to dust off the galoshes, pull the long underwear out of the closet and shake out the mothballs. Depending upon where you are geographically, the winter season brings rain, fog, sleet, snow, or all four. Some of you may look forward to thunder snowstorms and blizzard conditions from time to time, but universally, the weather patterns are changing and with them, winter hazards return.

For the snowbelt controller, slippery runway and taxiways will affect traffic with slower taxi and exit times. Snow removal equipment will add to the congestion on already busy airport surfaces. Runways and taxiways will be alternately closed and reopened. The controller will have to be that much more alert to prevent conflicts between vehicles and aircraft operating on the runways. Use the tools or "tricks of the trade" that work for you to keep the operation safe.

Remember, too, that snow and ice present more hazards to aircraft than hazardous braking on slippery surfaces. Loose snow or ice ingested into aircraft engines can cause serious damage. Propeller blades that strike snow banks can be easily bent and damaged beyond use. Snow banks may make runway/taxiway signs, markings, and intersections more difficult to discern, especially at night. Blowing snow can obscure aircraft from your view too.

Those of you who are laughing at the snowbelt guys and gals don't get off easy either. Ice is more prevalent aloft in those layers of stratus clouds and yes, Key West, thunderboomers too. PIREP's in the form of icing conditions (intensity and type), cloud bases, layers, and tops are valuable information to solicit from individual pilots. Share such information with other pilots and controllers as appropriate. If we all work hard at raising our awareness during this time, we can be assured of a safe, happy, holiday season.



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