![](media/image1.png){width="0.8888888888888888in"
height="0.8597222222222223in"}

**U.S. DEPARTMENT OF COMMERCE**

> **National Oceanic and Atmospheric Administration**

NATIONAL WEATHER SERVICE

1325 East-West Highway

Silver Spring, Maryland 20910-3283

![](media/image2.png){width="0.8395833333333333in"
height="0.8347222222222223in"}

MEMORANDUM FOR: Distribution

FROM: W/OPS2 -- John Van Kuren (Signed November 14, 2006)

SUBJECT: Initiation of the Operational Acceptance Test (OAT) for

Automated Surface Observing System (ASOS) Software

Version (V) 2.79C

ASOS Operational Trouble Report (OTR) #1078 dated 09/18/06 identifies a
condition where an erroneous Ice Free Wind (IFW) sensor maintenance flag
(\$) is appended to Aviation Routine Weather Reports (METAR) or Aviation
Selected Special Weather Reports (SPECI). This occurs when the IFW
sensor correctly reports an error for path 5 (one of the six paths in
the IFW sensor), but the path error is incorrectly interpreted by the
Acquisition Control Unit (ACU) software and an erroneous \$ is appended
to the next ASOS METAR or SPECI. Although the IFW sensor is operating
normally (it only needs data from four of the six paths for a valid wind
report) and no data quality error exists, this erroneous \$ might mask
other potential ASOS problems. In addition, the ASOS Operations and
Monitoring Center (AOMC) has experienced an increased workload in
responding to each erroneous \$, and in some cases, IFW sensors which
were functioning properly were replaced unnecessarily. The problem is
present in V2.79 and subsequent ACU software versions.

V2.79C (10/05/06) is identical to V2.79B (09/19/05) with the exception
of a fix for the

erroneous \$ problem. The fix has been confirmed in a System Test (ST)
at the Sterling Research and Development Center (SR&DC), Sterling, VA,
and the V2.79C software was also subjected to a battery of regression
tests to confirm ASOS functionality.

The V2.79C OAT plan is attached and is also posted at:

           
   [http://www.nws.noaa.gov/ops2/ops24/documents/asos_V2-79C.htm](http://www.nws.noaa.gov/ops2/ops24/documents/asos_v2-79C.htm)

The V2.79C software is available on the OPS12 ftp site and ASOS
Modification Note 80A is posted on the ASOS Electronics Technician
website.

Installation at the OAT sites listed below is authorized to begin during
the week of November 13, and evaluation of ASOS performance by NWS
Headquarters, on-site, or nearby staff will continue for approximately
two weeks.  A Test Review Group, made up of representatives from
Observing Services Division (OS7), Observing Systems Branch (OPS22),
Maintenance Branch (OPS12), and Aviation Services Branch (OS23) will
evaluate any reported problems as well as overall performance. If no
problems are noted during the OAT, V2.79C will be released immediately
for all operational ASOSs with an IFW sensor currently installed.

Installation of V2.79C at the following OAT sites is now approved:

[Eastern Region]{.underline} [Southern Region]{.underline}

KDDH Bennington, VT KDHT Dalhart, TX

KPWM Portland, ME KGUY Guymon, OK

[Central Region]{.underline} [Western Region]{.underline}

KBKE Baker, OR

KGFK Grand Forks, ND KCEC Crescent City, CA

KHYR Hayward, WI KDLS The Dalles, OR

KITR Burlington, CO KINW Winslow, AZ

KLHX La Junta, CO KMYV Marysville, CA

KLND Lander, WY KOKB Oceanside, CA

KMFI Marshfield, WI KRNM Ramona, CA

KMHE Mitchell, SD KSFO San Francisco, CA

KOFK Norfolk, NE KSHN Shelton, WA

KVPZ Valparaiso, IN KSJN St. Johns, AZ

[Alaska Region]{.underline}

PALH Anchorage (Lake Hood), AK

PANC Anchorage, AK

If you have any questions or comments, please contact the test
coordinator Bryan Moore, W/OPS24, at 301-713-0326 x176.

Distribution (email):

FAA - Calvin Smith

CIO12 -- K. Conaty

OS7 -- J. Heil

OS23 -- K. Schlachter

OST11 -- B. Giza

OPS12 -- A.Wissman

OPS12 -- G. Dalyai

OPS22 -- D. Mannarano

ER41 -- H. Machado

CR43 -- B. Brashears

SR41 -- M. Garcia

WR4 -- G. Deiotte

AR42 -- J. Hunter

PR -- A. Lowe

CC:

FAA - Bing Huang

E/CC11 - M. Urzen

CIO12 -- S. Murphy

OS12 -- L. Kozlosky

OPS -- J. McNulty

OPS1 -- M. Paese

OPS12 -- A. Leonardo

OPS13 -- M. Detommaso

OPS22 -- J. Facundo

OPS22 -- R. Parry

OPS23 -- R. Thomas

OPS23 -- P. Hoch

OPS24 -- J. Dinges

OPS24 -- M. Buckingham

OPS24 -- J. Lee

ER42 -- K. Murray

CR1 -- T. Townsend

SR11 -- V. Murphy

SR41 -- J. Villescaz

WR42 -- J. Lachacz

AR41 -- E. Doerr