ARW

120-Day Re-Assessment Plan

Site Visits

Background

A team visited the Raleigh County Memorial Airport (BKW), located in Beckley, WV, on May 21, 1997. BKW is a non-towered, Service Level D airport. The ASOS was commissioned on February 1, 1996. Instrument flight rules arrival and departure traffic for the airport is controlled by the Charleston Approach Control facility, and a remote transmitter/receiver is 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 at Elkins, WV.

Data from the FAA Airport Master Record as of December 19, 1996 indicates a total of 49 aircraft are based at the Beckley airport. Operations for the 12 months ending December 19, 1996 totaled 37,150 including 8,850 commuter, 3,400 air taxi, 20,000 general aviation local, 4,000 general aviation transit, and 900 military.

Beckley is located at an elevation of 2,504 feet above sea level in an area of the Appalachian Mountains known as the Appalachian Plateau. The terrain consists of numerous deep gorges eroded into an old plateau. The Allegheny Mountains rise to nearly 5,000 feet immediately to the southeast of Beckley. Due to prevailing westerly winds, the area experiences upslope flow and a tendency to have more cloudiness and precipitation than weather reporting stations on the eastern slopes of the Appalachians. The opposite is the case when winds are southerly; a downslope flow tends to create clearer weather around Beckley.

During extended periods of stagnant weather systems in the summer, haze can restrict visibility to less than three miles all day. Early morning radiation fog is common during summer and autumn but usually dissipates by mid-morning. Due to mountainous terrain, low stratus clouds and fog may obscure higher terrain and render mountain passes unusable for pilots operating under visual flight rules.

When low level winds are strong and northwesterly, this area will experience moderate to severe turbulence due to rough terrain. On any given day, pilots of light aircraft will report low-level turbulence below 5000 feet across the Appalachians.

The FAA Regional Office received congressional correspondence concerning the Raleigh County Memorial Airport ASOS. The correspondence specifically addressed the fact that the ASOS provides no freezing rain sensor, no thunderstorm detection, and no tornado reporting. The Airport Manager informed the visiting team during the site visit that he started the political involvement with his letters and telephone calls.

Participants

Airport manager, four contract weather observers, one recent graduate with meteorological degree, air cargo carrier pilot, local newspaper reporter, and FAA/NWS team.

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.

The contract weather observers in attendance stated -

"They were knowledgeable of the ASOS."

One user appeared to have a general understanding of the system.

Several of the attendees stated -

"The ground-to-air transmitter was interfering with the UNICOM and has been turned off. While the observations are transmitted to Charleston, WV approach via a teletype system, this creates a time lag when multiple SPECIs (Aviation Selected Special Weather Report) occur in a short period of time."

Discussion during the meeting addressed the representativeness (validity) of the ASOS. It was stated that -

"The visibility is susceptible to radiation fog developing in the valley and moving over the ASOS site (ILS [Instrument Landing System] RWY 1) and thereby reducing controlling visibility to below airport minimums. Observed visibility may be higher, however, an instrument approach to another runway must be executed (VOR RWY 10) when the airport is officially below minimums."

Another attendee complained -

"The freezing rain sensor doesn’t detect freezing rain most of the time and usually calls it UP (unknown precipitation)."

"The ceilometer (laser beam ceilometer) occasionally reports three layers of clouds when only one layer exists. This is most common with cumulus clouds. As an example, on May 19, 1997, the ASOS reported a clear sky when a thunderstorm was occurring (observer estimated OVC065)."

Other problems noted were -

"The wind sensor reports velocity consistently lower than direct read instruments (direct wind equipment is located mid-field) and the system reported ‘wind shifts pressure rising/falling rapidly’ when the event never occurred."

Other specific comments regarding the ASOS were -

"The system does not provide off-airport remarks, such as clouds on ridge, building cumulus clouds, AltoCumulus Standing Lenticular clouds, etc. It does not report ceiling above 12,000 feet and it does not have a lightning sensor."

Another participant noted -

"The stand alone system would prevent instrument approaches to RWY (Runway) 10, thereby increasing flight cancellations and causing severe financial ramifications to the airport and the community."

Further complaints about the ASOS were -

"The system took five minutes to reflect changes in visibility in rapidly changing conditions and generated too many SPECIs (Aviation Selected Special Weather Report) while catching up to current conditions."

"Visibility from ASOS averages over ten minutes; this is dangerous when visibility is rapidly decreasing to or below minimums."

The reliability of the ASOS was called into question. An attendee stated -

"The commercial power for ASOS is wired through the ILS (Instrument Landing System) system and is prone to failures."

Information Provided

The team provided information on ranking criteria and discussed algorithms and sensor functionality.

The airport manager initially refused information on Non-Federal Observer Program but later agreed to look at the program.

Issues Identified

The issues raised by the contract weather observers at Beckley concerned all aspects of the ASOS. Inaccuracies were reported concerning the visibility sensor, ceiling detection and reporting, precipitation detection, wind velocity, pressure jumps, dew point reporting and freezing precipitation sensors. The responsiveness of the ASOS in reporting rapidly changing conditions and its inability to report off-airport remarks was noted. The users contend that the single visibility sensor located on the approach end to runway 19 frequently reports visibility non-representative of the rest of the airport due to the advection fog created by the unique terrain. There was concern that the inability to use both runways could lead to the loss of revenue for the airport. Specific maintenance issues addressed were the frequency interference between the ASOS ground-to-air and the UNICOM (the ground-to-air is currently turned off), the propensity of commercial power to fail, and the calibration of the sensors.

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