Selection of A FLT Level

CHAPTER FOUR

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).

408.

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:

Wind component

Thunderstorms

Minimum ceilings/maximum cloud tops

Turbulence

Visibility at flight level

Icing

Minimum freezing level

Precipitation

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.

409.

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