6-1.     Introduction

6-2.     Summary of Backup Requirements

6-3.     Validity of Data

Figure 6-1.    Summary of Long-line Backup Requirements

6-4.     Equipment Requirements

6-5.     Procedures for Providing Backup Information

Figure 6-2.    Backup Reporting of Wind or Altimeter Setting

6-6.     Coding of Missing Data

6-7.     Procedures for Wind Speed and Wind Direction

Figure 6-3.    Estimating Wind Speed

Figure 6-4.    Backup Reporting of Tower/Surface Visibility

6-8.     Procedures for Visibility

Figure 6-5.    Backup Reporting of Weather Phenomena

6-9.     Procedures for Present Weather and Obscurations

Figure 6-6.    Backup and Augmentation Weather and Obscurations

Figure 6-7.    Backup Reporting of Sky Condition

6-10.   Procedures for Sky Condition

Figure 6-8.    Priority for Reporting Cloud Layers

Figure 6-9.    Criteria for Variable Ceiling

Figure 6-10.  Increments of Reportable Values of Sky Cover Height

Figure 6-11.  Reportable Contractions for Sky Cover Amount

6-11.   Procedures for Temperature and Dew Point

Figure 6-12.   Backup Reporting of Temperature and Dew Point

6-12.   Procedures for Altimeter Setting

6-13.   Procedures for Documentation

6-14.   Procedures for Communications

6-15.   Disposition of MF1M-10C

6-16.   Examples of Backup Observations

6-17.   Malfunctions/Outages

Figure 6-13.   AWOS Backup Observation Examples

Figure 6-14.   ASOS Backup Observation Examples

6-18. - 6-19. Reserved