METEOROLOGY FLIGHT PLANNING
the other blocks, Block 23 includes spaces for indicating types, intensities, and locations of icing.
Neither Block 23 nor Block 24 includes an area for advisories or warnings, as any that may be
applicable to icing or precipitation would be listed in other areas of the DD 175-1. Expected
precipitation for Block 24 can be determined from any or all surface weather products, including
the Surface Prognostic Chart, Low-Level Significant Weather Prognostic Chart, Radar Summary
Chart, MWA, and possibly even the WA (Sierra).
SELECTION OF A FLT LEVEL
Now that we have described the various weather sources used by meteorologists to fill out the
Part II, En route Data section of the DD 175-1, it will be easier to discuss the various
considerations in the selection of an en route flight level. When building an overview of the
weather after preflight planning, before turning in the flight plan to METRO, an aviator should
strive to build a good idea of where the most hazardous conditions exist, in order to avoid them,
when possible. Depending on the mission of the flight, and whether intending to fly IFR or VFR,
the location, severity, and intensity of the following aspects of the weather will guide the
selection of a flight level:
Minimum ceilings/maximum cloud tops
Visibility at flight level
Minimum freezing level
Notice this list of considerations corresponds with the set of Blocks 15 through 24 in Part II of
the DD 175-1. Taking into account all the hazards associated with the foregoing conditions, an
aviator can make an informed decision to select a group of altitudes that excludes as many of
these hazards as possible.
PART III: TERMINAL FORECASTS SECTION
The Terminal Forecast section of the DD 175-1 provides space for information about forecast
weather conditions at both the destination and alternate airfield, plus any planned intermediate
stops. The format follows closely the TAF format from which the information is gathered,
except that it is presented in columns for easier reading (Figure 4-6).
Figure 4-6 Part III: Terminal Forecasts Section
4-10 FLIGHT WEATHER BRIEFING FORM, DD FORM 175-1