August 21, 1985                         W/OTS21x1

TO:    All Holders of Operations Manual

SUBJECT:     Transmittal Memorandum for Operations Manual Issuance 85-8

1.    Material Transmitted:

WSOM Chapter B-14, "Supplementary Aviation Weather Reporting Stations," 10 pages.

2.    Summary:

This chapter has been rewritten so that the guidelines and policies previously contained in OML's and memoranda could be consolidated. Changes in wording, policy, and new items are highlighted by an asterisk (*). The major change is:

Scheduling of Observations, paragraph 4.3.2. This change incorporates an FAA recommendation that schedule of flight operations conducted under FAR Part 135 be bracketed by a corresponding schedule of weather observations. NWS and cooperator participation in keeping the schedule current are contained in paragraph 3.2.1h.

3.    Coordination:

This chapter was reviewed by and contains recommendations made by the FAA and NWS Regions.

4.    Effect on Other Instructions:

Cancels WSOM Chapter B-14, transmittal issuances 68-27, dated August 8, 1968, and 68-32, dated August 27, 1968.

Also cancels the following OML's filed with B-14. OML 69-5, dated February 4, 1969, Operation SAWRS Program. OML 10-75, dated April 30, 1975, Unsatisfactory Inspection Criteria (SAWRS).

Richard E. Hallgreen
Assistant Administrator
  for Weather Services

Issue Date    Org. Code     NATIONAL WEATHER SERVICE         Part     Chap.
8-21-85        W/OTS21x1         Operations Manual                                B         14

Table of Contents:

1.   Purpose
2.   Criteria for Establishing
*3. Procedures for Establishing

        3.1    Processing Applications for SAWRS
        3.2    Agreements
                3.2.1     Cooperator's Responsibility
                3.2.2     Responsibility of the Government
4.    SAWRS Observation Program

        4.1    Elements to be Observed
               4.1.1    Other Elements
* 4.2                   Multiple SAWRS at the Same Location
               4.2.1    Multiple SAWRS Operation
            * 4.2.2    Observation Dissemination at Multiple SAWRS Operations
                4.2.3   SAWRS at Government-Owned Facilities

4.3    Schedule of Observations

        * 4.3.1    For FAR Parts 121 and 135 Non-Scheduled Operations
        * 4.3.2    For FAR Parts 121 and 135 Scheduled Operations
        * 4.3.3    For Terminal Forecasts

4.4    Transmission of SAWRS Observations
4.5    Instrumentation

            4.5.1    Cloud Height
        * 4.5.2     Temperature and Dew Point
            4.5.3    Wind
            4.5.4    Altimeter

5.    Supervision

        5.1    Supervising Station

6.    Inspection of  SAWRS

        6.1    Inspection Standards

Exhibit:

B-14-1 Cooperative Agreement for Aviation Weather Observations

Appendix:

* A - Guideline for FAR Part 135.213 (b)

1.     Purpose. This chapter prescribes the procedures and policies governing the establishment and operation of Supplementary Aviation Weather Reporting Stations (SAWRS).

2.     Criteria for Establishing. A SAWRS is established at an airport when the Federal Aviation Administration (FAA) has determined that the weather observations are needed:

    a.     at the airport to satisfy Federal Aviation Regulations (FAR) Parts 121 or 135, or

    b.     for the safe conduct of other aircraft operations.

* 3.     Procedures for Establishing. Applications that satisfy the criteria for establishing and operating a SAWRS will be approved or rejected by the Weather Service Regional Headquarters (RH). RH will also investigate the use of using weather observations from one airport to permit FAR Part 135 operations at another. The procedures to be followed in these cases are contained in Appendix A.

3.1     Processing Applications for SAWRS. RH, upon receipt of a request for establishing a SAWRS, will determine through coordination with the FAA area or region that:

    a.     a SAWRS is needed at the location in question,

    b.     the applicant will provide, install, and maintain meteorological equipment required to observe or measure the required elements, and

    c.     the applicant will provide personnel to take, record, and disseminate the observations.

3.2     Agreements. Confirmation of an understanding between the RH and the cooperator will be accomplished on WS Form B-l2, "Cooperative Agreement for Aviation Weather Observations," (Exhibit B-14-13. Instructions for its preparation are on the back of the form.

3.2.1     Cooperator's Responsibility. For an approved SAWRS location to:

    a.     provide necessary equipment to measure cloud height, wind, temperature, dew point (if required), and altimeter setting.

    b.     provide suitable quarters, including space for properly installing instruments and equipment, required by the SAWRS program,

    c.     provide, install, operate, relocate if necessary, protect and maintain, all instruments and equipment in accordance with NWS specifications,

    d.     provide transmitting facilities and transmit the observations to own company aircraft, and if required, to a designated National Weather Service (NWS) or FAA facility.

    e.     provide qualified personnel to observed record, and disseminate the weather observations in accordance with the Aviation Weather Observations, Federal Meteorological Handbook #9 (FMH-9),

    f.     mail the original of all observational forms to a NWS facility as directed,

    g.     make all observations that are taken and recorded available to all other local aviation interests,

    h.     promptly inform the NWS supervising office when a change in flight schedules necessitates a change in the schedule of observations, (Note: RH's may establish reporting time limit),

    i.     annotate and return the certificates of former employees to the issuing authority,

    j.    permit Government officials-free ingress and egress to the station for the purpose of inspection and guidance of the observation program and to check on associated equipment and instrumentation, and

    k.     provide additional services as 11sted on WS Form B-12.

3.2.2     Responsibility of the Government. For an approved SAWRS, the Government (NWS) will:

    a.     train and certificate qualified employees, provided by the cooperator, to observe and record the required elements of the observation,

    b.     furnish training material, handbooks, instructions; and forms required for taking and recording observations,

    c.     furnish technical advice and guidance in the selection, installation, operation, and maintenance of meteorological instruments and equipment,

    d.     provide inspection and guidance of the observation program (see paragraph 6), and

    e.     provide additional equipment and services as listed on WS Form B-12.

4.     SAWRS Observation Program. Each RH will establish a program of aviation weather observations at each SAWRS using the following guidelines.

4.1     Elements to be Observed. As a minimum, the following elements will be observed in accordance with FMH-9 at all SAWRS:

    a.     cloud cover and cloud height,

    b.     visibility,

    c.     weather and obstructions to vision,

    d.     temperature,

    e.     dew point (if required for preparation of terminal forecasts),

    f.     wind direction and speed,

    g.     altimeter setting, and

    h.     significant remarks.

4.1.1     Other Elements. Any additional elements required should be specified in the agreement.

* 4.2     Multiple SAWRS at the Same Location. When two or more aviation interests are either requesting the establishment of a SAWRS or the extension or change of an existing program either mutually sponsored or supported by another interest, all applicants should indicate in writing to the RH the extent they will or have agreed to cooperate with the other interest in providing the required observations.

4.2.1     Multiple SAWRS Operation. As a general policy, a single set of instrumentation should be used in taking official observations from a given location. Cooperators should make mutual.arrangements for providing and sharing common observing equipment. If this is not practical due to distance or other reasons, exceptions to the above policy may be made. Station documentation shall include the details on which instrumentation set is used for each specific observation program. Further, only one observation at a given time is the official observation for that location. In no case will two or more sets of official observations be taken on the same airport at the same time.

* 4.2.2    Observation Dissemination at Multiple SAWRS Operations. Cooperator arrangements for on airport dissemination of the official observation should be established and understood by all parties. As a minimum, the observation log, MF1-l0C, currently being used as the official observation, should be on display so as to be available for viewing by all aviation interests on the airport.

4.2.3     SAWRS at Government-Owned Facilities. SAWRS supplementing NWS or FAA observing programs may use government facilities and equipment subject to the concurrence of the agency concerned, provided such usage does not endanger the security of government property.

4.3     Schedule of Observations. The FAR's usually determine the schedule and use of the observations.

* 4.3.1    For FAR Parts l21 and l35 - Non-Scheduled Operations. One observation is required to be taken, recorded, and reported to the aircraft, if practical, 30 minutes prior to approach or departure, but in no case later than the commencement of each approach or departure. Under changing conditions, additional special or local observations will be taken, recorded, and reported to the aircraft with the frequency specified by instructions in FMH-9 until the approach or departure is completed. Observations may be discontinued upon the completion of each operation.

* 4.3.2    For FAR Parts 121 and 135 - Scheduled Operations. When scheduled flight operations are conducted, observations (record, special, and local) are to be taken in accordance with instructions in FMH-9 and reported beginning at least 1 hour prior to scheduled arrival and continuing until the actual departure of the aircraft. If the departure is scheduled more than 1 hour after the arrival, observations may be discontinued after the arrival until immediately prior to the scheduled departure.

* 4.3.3    For Terminal Forecasts. When terminal forecasts are required for a SAWRS, a minimum schedule of observations should be prepared by the RH. At least two consecutive observations, not less than 30 minutes or more than about 1 hour apart, are required for terminal forecast startup. (See WSOM Chapter D-21 for details).

4.4     Transmission of SAWRS Observations. RH will set up a schedule for the transmission of observations from a SAWRS when such observations are needed at locations other than the point of origin, e.g., for the preparation of terminal forecasts used in air traffic control centers.

4.5     Instrumentation. RH should ensure the instruments used by a SAWRS meet or exceed the following minimum standards.

4.5.1     Cloud Height. Cloud height will be determined by using balloons for daylight operations and by ceiling lights for night operations. Either of the following systems will suffice for the measurement of nighttime cloud height when used with a standard clinometer. A baseline of 500 feet is recommended when using the standard ceiling light.

    a.     standard ceiling light.

    b.     an improvised ceiling light, approved by the RH which will provide an identifiable spot of light on clouds 2000 feet above field elevation or on clouds below field minimums under visual flight rules (VFR), whichever is higher.

* 4.5.2    Temperature and Dew Point. Temperature and dew point values shall be obtained from approved thermometers located in a small airway or larger type shelter. Specifications for thermometers require that readings should not vary more than ⁺1.0^oF throughout the thermometers' temperature range. Additionally, readings from thermometers paired for a psychrometer should read within 0.5EF of each other under like conditions.

4.5.3     Wind. With respect to wind speed, values indicated by the indicator should be within 10 percent of the true value when the wind speed is less than 100 knots. With respect to direction, the indicator must indicate within 10^o of the true wind flow. The readouts should indicate direction within 10^o of the true wind flow and the speed to the nearest knot.

4.5.4     Altimeter. Selection, calibration, installation, and setting of altimeters shall be in accordance with FAA Advisory Circular 9l-l4, current edition.

5.     Supervision. The RH should arrange for a representative of the NWS to visit each SAWRS within the region at least twice a year to provide any necessary guidance -and inspect the SAWRS operation. The RH may assign supervision of a SAWRS to a nearby NWS office. Whenever SAWRS observations are to be transmitted longline, the RH may arrange to have such observations monitored by the NWS or FAA before entry on the public weather circuits, if such action is deemed necessary.

5.1     Supervising Station. The RH may designate an office as a supervising station or t e SAWRS. When this is done, the RH should inform the supervising station of its responsibilities in the program and inform the SAWRS of the action taken.

6.     Inspection of SAWRS. A SAWRS will be inspected by a; representative of the RH or by the supervising station. All inspection visits are to be documented by a written report. A copy of each report is to be forwarded to NWS, Basic Observations Branch, W/OTS21x1. The purpose of these inspections is to:

    a.     determine whether the observational program is being conducted in accordance with standards outlined in this chapter and in FMH-9,

    b.     inspect the installation, maintenance, and exposure of meteorological instruments,

    c.     explain NWS policies and procedures as they apply to the station, and

    d.     assist in matters relative to the station weather observing program.

6.1     Inspection Standards. Any of the following conditions would warrant an inspection rating of unsatisfactory. Any unsatisfactory rating should be followed up with a letter to the SAWRS cooperator with a copy to appropriate FAA regional office. The letter should explain that the "grace period" is the time limit in which the SAWRS cooperator must rectify the condition. If the condition persists beyond the time limit, the RH will initiate action to suspend the Cooperative Agreement for Aviation Weather Observations. Notification of the suspension should also be sent to the appropriate FAA office and WSH (W/OTS21x1).

Element	Condition	Grace Period
Cloud Height	Does not possess the capability for taking balloon ceilings (daytime) and/or ceiling light measurements at night	l5 days
Temperature	Cannot provide required temperature	30 days
Wind direction and speed	Does not meet criteria for direction or speed	30 days
Altimeter Setting	1. Using aircraft altimeters not calibrated in accordance with FAA Advisory Circular 91-14, current series, or	None Immediate Suspension
	2. Instruments out of calibration
Observing    Procedures	1. Other than certified observers taking official observations	None Immediate Suspension
	2. Lack observers proficiency	None Immediate Suspension
	3. SAWRS cooperator unwilling to make observations available	None Immediate Suspension

Part 135, paragraph 213(b) stipulates that, in some cases, air taxi and commercial operator pilots may conduct instrument flight rules operations at an airport using weather observations taken at another airport. Such procedures will only be authorized when, after investigation by the US National Weather Service and the FAA Flight Standards District Office...it is found that the standards of safety for that operation would allow the deviation....

The recommendation concerning the representativeness of observations should be made at RH using the following guidelines.

a. If locations are more than 10 miles apart, it is usually unlikely that important aviation weather parameters such as ceiling, visibility, and even wind, to a lesser extent, taken at one point can be counted on to be representative of what is occurring at the other, and

b. if they are less than 10 miles apart, and the closer the better, a thorough check of the terrain and/or obstructions between the two airports should be made before advising the appropriate FAA office.

Each request should be coordinated between Regional Meteorological Service Division and Data Acquisition staffs. Recommendations should be made to the appropriate FAA office, for action, not to the operator involved, and should be confined to stating whether or not the weather observations from one location can be expected to be generally representative of the weather occurring at the other location. Recommending any other particular course of action to the FAA should be avoided.

WSOM Issuance
85-8    8-21-85