Aero Chapter 06 (ADV & IUT) and 07 (TS), Performance
T-45 Aerodynamics Student Workbook
AERO CHAPTER 06 (ADV & IUT) AND 07 (TS), PERFORMANCE
INTRODUCTION TO T-45 PERFORMANCE CHARTS
The NATOPS Flight Manuals for the T-45 contain a wealth of performance information and helpful tips.
Study the sections assigned by your instructor and expect to be tested thoroughly on the charts.
While the T-45’s NATOPS Flight Manual is the best source of information for your study prior to flight, you
can’t take it with you. Know what is in the pocket checklist and how to find it quickly. The order to divert
from the carrier to a shore base should not trigger a panic because the bingo charts are included in three
separate locations of the pocket checklist, but are not identified on a tab by name.
CHART USAGE
The performance charts in the NATOPS manual are difficult to use, but must be understood before using
them. The charts are arranged in the same order for most of the Navy’s tactical aircraft. Most of the
charts are in the logical sequence in which one would fly a cross-country. The mission-related charts are
at the end of the manual. Grouped in sections, the introduction gives the background, definitions,
explanations, conditions, assumptions, and sample problems to enhance your understanding of that
section’s charts. One should establish an understanding of the problem and the use of the chart before
wasting a lot of time making mistakes in the chart.
The guide, in the upper right corner of many charts, shows the path to use when traversing that particular
chart. A better explanation of the route through each chart is in the introduction to that chapter. When
one moves from one grid to another grid with channels, normally one parallels the channel until reaching a
value on the left side of the grid. Proceed straight down to the bottom of the grid. Check the sense of
your answer and redo the problem if necessary.
Techniques That Work Best in Using the Charts:
• Study the chapter introduction and sample problem.
• Select the correct chart. This is the most frequent mistake.
• Verify you selected the right configuration and conditions.
• Study the guide and chapter introduction to determine the proper route.
• Do you need a value from another chart or elsewhere?
• Lay the chart flat under good light.
• Count lines from the heavy black lines to navigate from location to location and avoid straight edging
long distances across the chart.
• Compute the grid value throughout the problem to ensure a correct answer.
• Realize you may solve a problem in the middle of a chart, at the end of the guide’s course, or on
another chart.
• Ask yourself if the answer makes sense. If not, do it again.
DENSITY RATIO CHART
The use of density ratio combines the effect of temperature and pressure altitude on engine performance.
Jet engines perform better at higher density ratios, that is, with lower temperatures or lower pressure
altitudes. Density ratio must be computed before using the takeoff and landing charts.
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