The National Academies Press

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From page 33... ... 33 This chapter will discuss the common types of automated weather observation systems in use at general aviation airports today. The word "automated" is significant, as the FAA does sponsor various programs that incorporate human observers in weather reporting. Read the entire page →
From page 34... ... 34 Airport Surface Weather Observation Options for General Aviation Airports pressure altitude called the density altitude may also be reported. Density altitude is pressure altitude corrected for a nonstandard temperature. Read the entire page →
From page 35... ... Existing Technologies 35 is that temperature (and pressure) deviations from standard conditions at a given altitude will create conditions in which the aircraft will perform as if it is at a different altitude. Read the entire page →
From page 36... ... 36 Airport Surface Weather Observation Options for General Aviation Airports The sensor suite should be located away from cultivated land to avoid impacts from airborne debris affecting sensor readings. Some sensor mounting heights may be increased to keep them sufficiently above the average snow depth. Read the entire page →
From page 37... ... Existing Technologies 37 For an airport with a glide slope installation, the entire ASOS may be co-located behind the glide slope shelter installation, per Figure 1 in FCM-S4-1994, as duplicated here in Figure 9. From a practical standpoint, locating the wind sensor often proves to be the controlling factor in siting an ASOS, because it is the tallest object and also requires the largest area of protected and controlled ground around it. Read the entire page →
From page 38... ... 38 Airport Surface Weather Observation Options for General Aviation Airports 3. Service Level B: All elements of Level C, but augmentation is beyond the reporting elements of the ASOS. Read the entire page →
From page 39... ... Existing Technologies 39 government but is installed, maintained, and operated under a series of rules which allow it to report data to the federal government (i.e., to the NWS, NADIN, and WMSCR) Read the entire page →
From page 40... ... 40 Airport Surface Weather Observation Options for General Aviation Airports The use of a remote altimeter setting may be beneficial if the local pressure sensor is out of service, or to initiate an instrument approach at an airport without any on-field weather reporting. The RASS penalty is a function of the distance of the source from the airport, the difference in elevation of the source and the airport, and other local factors that the FAA has determined may influence pressure variations. Read the entire page →
From page 41... ... Existing Technologies 41 Discussions with Vaisala indicate that its AWOS A/V is actually certified as an AWOS II, so the system includes all the sensors and capabilities of an AWOS II. Where a system has not been certified by the FAA, dissemination of that data in any format must first be prefixed with the word "advisory" (AC 150/5220-16E, Section 1.2.f) Read the entire page →
From page 42... ... 42 Airport Surface Weather Observation Options for General Aviation Airports reporting into FAA-controlled systems. These standards are detailed in FAA Order 6700.20B -- Non-Federal Navigational Aids and Air Traffic Control Facilities as well as in AC 150/5220-16E. Read the entire page →
From page 43... ... Existing Technologies 43 The approved third-party service provider system allows an extra level of security to prevent unauthorized access to safety data or corruption of that data. It is notable that not all owners may elect to establish a WMSCR connection for their certified AWOS III (or better) Read the entire page →
From page 44... ... 44 Airport Surface Weather Observation Options for General Aviation Airports responsibilities include keeping grass cut to acceptable lengths, ensuring no obstructions to the sensors are created, and protecting against noncompatible land uses that may affect the system. Cost The most common type of AWOS installation is the AWOS III or some variant thereof (P, T, or P/T) Read the entire page →
From page 45... ... Existing Technologies 45 items would be performed at one of the regularly scheduled triannual inspections already noted in Table 9. Repair costs are not included in this summary, as these are dependent on operating environment, quality and consistency of maintenance, general upkeep, and chance. Read the entire page →
From page 46... ... 46 Airport Surface Weather Observation Options for General Aviation Airports Similarly, whereas certified systems are commissioned to verify that their sensors are performing correctly and are then inspected triannually thereafter against set performance standards, noncertified systems receive no official calibration and are not continuously checked against any benchmark. They may read erroneously from the initial installation or stray over time, but there is no official process to document, track, and correct this. Read the entire page →
From page 47... ... Existing Technologies 47 – Relative humidity – Density altitude – Condensation altitude This readback should be interpreted to mean the installation is providing certified visibility and altimeter information (AWOS A/V) but is co-located with a collection of noncertified equipment reporting other data. Read the entire page →
From page 48... ... 48 Airport Surface Weather Observation Options for General Aviation Airports The system is included with the noncertified systems because this shared-frequency functionality is sometimes used to broadcast weather information from noncertified systems. Shared use of the UNICOM frequency may be beneficial, because there is competition for the limited VHF band dedicated for aviation uses. Read the entire page →
From page 49... ... Existing Technologies 49 is run by the FAA's Aviation Weather Camera Program Office, and displays a map titled "FAA Aviation Weather Cameras." The site is an interactive map that allows users to click on a reporting location to see near-real-time camera images taken from any of 233 locations across Alaska (as of February 2019) and 54 locations across British Columbia and Yukon Territory in Canada. Read the entire page →
From page 50... ... 50 Airport Surface Weather Observation Options for General Aviation Airports The camera is mounted on the top of the Port of Skagit Administration/Airport Terminal building. The camera provides four views -- Runway 11 (Northwest) Read the entire page →
From page 51... ... Existing Technologies 51 AIP requirements for support of AWOS are contained in Table K-2 of the AIP Handbook. In order to be eligible for AIP reimbursement, the system must conform to the following general requirements: • Must pass a Benefit-Cost Analysis (BCA) Read the entire page →

From page 33...

... 33 This chapter will discuss the common types of automated weather observation systems in use at general aviation airports today. The word "automated" is significant, as the FAA does sponsor various programs that incorporate human observers in weather reporting.