Figure 6-13

STUDENT GUIDE

VISUAL NAVIGATION

6.6.2. T-1A/T-39 VNAV Fuel Planning for Stereo Routes

6.6.2.1. A primary purpose of the jet cards produced in VT-4 / VT-10 is to determine mission

completion feasibility. Simply put, "Do we have enough fuel to complete the mission?" In T-34

mission planning the mission was broken up into three segments: departure to low-level entry,

low-level, climb out and return (approach). For T-1A/T-39 VNAV sorties using out of area

routing or non-stereo flight plans, this same breakdown is sufficient. However, for sorties

incorporating two low levels, certain assumptions can be made regarding the portion of flight

between the two low-level routes.

6.6.2.2. For T-1A/T-39 VNAV missions using stereo routing, the most common profile, the fuel

planing profile is broken into five segments: (Figure 6-13)

6.6.2.2.1. Takeoff, departure to entry point of first low-level.

6.6.2.2.2. The first low-level route

6.6.2.2.3. The interim VFR leg.

6.6.2.2.4. The second low-level route

6.6.2.2.5. The IFR return portion

6.6.2.3. T-1 and T-39 fuel figures for climbing and cruising at various altitudes and airspeeds are

provided in Figures 6-14 and 6-15. (Data from these figures may be used to work the problems

in this text, but the In-flight Guide is the only approved source for flight computations.) The

total fuel required to arrive at the initial approach fix is computed by totaling the segments.

Specified IFR

VFR

Altitude to IAF

Specified

(700 # Fuel

Altitude

IDLE

Altitude

Required)

And TAS

Descent to

Entry Point

Fuel Flow

Takeoff

from In-flight

Guide

TRADR

1800 pph

Second Low

(300 TAS)

Level Route

IAF

T-1A/T-39 VNAV Fuel Planning Profile - Stereo Routing

Figure 6-13

6-18