ARW
120-Day Re-Assessment Plan
Site Visits
2.3.5 Frank Wiley Field, Miles City, MT
Background
A team visited Frank Wiley Field (MLS), located in Miles City, MT, on May 6, 1997. MLS is a non-towered, Service Level D airport with FAA contracted weather observers. The MLS Flight Service Station was closed in April, 1993. The ASOS was installed in September, 1993 concurrent with the closure of the Flight Service Station, but the ground-to-air transmitter was not installed until November, 1994. The airport is attended during daylight hours only, however, the contract weather observer is on-site 24 hours a day. The ASOS was scheduled to be commissioned in March, 1997 and the weather observation contract was to be canceled concurrent with the ASOS commissioning. Both have been deferred pending the recommendations of the re-assessment.
Instrument flight rules arrival and departure traffic is controlled by the Salt Lake City Air Route Traffic Control Center using a remote transmitter/receiver located on the field for clearance delivery and flight plan cancellation. Pilot pre-flight weather briefings and Notices to Airmen issuance services are provided by the Automated Flight Service Station.
Data from the FAA Airport Master Record as of September 11, 1996 indicates that a total of 23 aircraft are based at the Miles City Airport. Operations for the 12 months ending September 11, 1996 totaled 11,038 including 1248 commuter, 1,840 air taxi, 3,170 general aviation local, and 4,780 general aviation transit.
Miles City is located on the eastern Montana plains. Due to the surrounding terrain and dry air, remarks in the weather report sometimes give information on weather formations well beyond the actual airport environs. In an area where the next weather observation in any direction is well over one hundred miles away, this is, at times, significant. Most unique about Miles City and its environs is its isolation from other weather reports and the distance between weather radar sites.
The FAA Regional Office received Congressional correspondence expressing concern about the inadequacy of the ASOS at the Frank Wiley airport, specifically addressing the issues that the system provides no freezing rain, thunderstorm or tornado reporting.
Participants
Airport manager, contract weather observer, six local pilots, and FAA/NWS team.
Synopsis of User Comments
This section of the report is a record of the comments received during the meetings, interviews and discussions that took place during the site visits. It is intended to present a summary of the input from the users on a particular subject. These comments may include technical inaccuracies and user perceptions that do not reflect actual conditions.
It appeared to the team that the users have a very low level of understanding of the ASOS and the system’s capabilities. In fact, most of the local users did not appear to be aware that the ASOS was operating in a test mode and that the system was not considered operationally usable.
As part of the re-assessment strategy, system access (i.e., access by the contract weather observers to the computer display of the weather observation generated by the ASOS) was shut off in order to conduct a "blind comparison" test. The "blind comparison" test compared the ASOS observation with the human observation.
Prior to shutoff, most pilots used the ASOS as if it was commissioned, that is, certified as operational, and most were not aware the system was transmitting in the test mode only. Currently, the 11% failure of the longlines used to transmit the observations will prevent the system from passing the pre-commissioning test. Its commissioning will be delayed until this is corrected. The NWS representative to the team addressed this issue as an ongoing problem with the local Phone Company.
Several pilots expressed their satisfaction with the representativeness of the system. One local pilot stated -
"He was concerned that the system reported non-representative data." He gave no documentation.
Several attendees expressed concern that -
"One NWS specialist is responsible for maintaining all the ASOS sites in Montana. Potential revenue could be lost because of excessive maintenance delays and the 36 hour maximum response time to outages."
Specific comments received regarding the ASOS were -
"The system does not provide distant weather remarks or freezing rain, thunderstorm and tornado reporting."
A uniform complaint among the attendees was that -
"Longline weather reports were missing."
However, further discussions revealed that the current observations are phoned to Great Falls Automated Flight Service Station by the contract weather observers, and everyone agreed that this is not an ASOS problem. MLS is very remote and the nearest suitable alternate airport is Billings, MT. It has poor Next Generation Weather Radar coverage and does not have any radar approach control services.
One of the contract weather observers stated -
"He provides remarks on distant weather over nearby mountains plus advisory service to the local community in event of approaching severe weather."
Positive observations by a local pilot were -
"How well the ASOS indicated rapidly changing conditions and the accuracy of the ASOS ceiling height reporting."
Users also wanted to know -
"When the ASOS will be turned back on."
Several attendees stated that -
"After having been promised ‘equal or better service’ by the FAA after the closure of the Flight Service Station, they see the termination of the weather observer contract upon commissioning of the ASOS as a further decline in FAA services."
Information Provided
The users were provided with a general overview of ASOS functionality and sensor capabilities, and information on Service Standards and ranking criteria. The team supplied information on Automated Lightning Detection and Reporting System and the freezing precipitation sensors. They explained the various re-assessment methodologies and why the ASOS reports were not available.
Issues Identified
The lack of off-airport remarks, thunderstorm detection equipment, and a freezing precipitation sensor were the primary concerns expressed at Miles City. The termination of the weather observer contract after the commissioning of the ASOS is viewed as a continuation of the FAA’s failure to provide "equal to or better" service after the closure of the Miles City Flight Service Station.