1 Selected Airfield NAS Jacksonville 2 ICAO identifier KNIP

1. Selected Airfield: NAS Jacksonville

2. ICAO identifier: KNIP

3. Field elevation [feet MSL]: 22 feet (6.7 m) (Estimated)

4. Current weather report at the time of work on this assignment:

a) Date and time: 17 August, 2016 1853

b) Current altimeter setting: 30.11 Hg

c) Current temperature: 90 degrees Fahrenheit A. Find the Pressure Altitude of your airfield [ft]. -168 feet below sea level

B. Based on your determined pressure altitude, find the Pressure Ratio, (delta). Pressure ratio at sea level P actual/P standard sea level =30.11/29.92=1.0064

C. Using your researched current temperature and the known standard sea level temperature, determine the Temperature Ratio, (theta). (Remember to convert °F into an absolute temperature, i.e. °R or °K, and stay consistent within one system of measurement.)

D. From your B and C results, find the Density Ratio, (sigma).

E. With your D result, re-enter the Standard Atmosphere Table (“Flight Theory and Aerodynamics”, Table 2.1) to find the corresponding Density Altitude. Interpolate as necessary.

F. To highlight the influence of humidity on air density, enter your airfield (elevation) and weather data (temperature and altimeter setting) into the online density altitude calculator tool http://wahiduddin.net/calc/calc_da_rh.htm (Make sure to select the correct units in the top/input area of the calculator and read the correct units in the bottom/results area).

I) Find Density Altitude [ft] with 0% relative humidity.

II) Find Density Altitude [ft] with 100% relative humidity.

III) Compare your findings I) and II). Describe what effects humidity has on air density.

1. This time, we will take a closer look into the speeds involved. Let’s assume the given 150 kts lift-off speed was the indicated value in the cockpit, i.e. the Indicated Airspeed [KIAS].

G. Find the Calibrated Lift-Off Speed [KCAS] using the chart below, which is a typical example of an aircraft position error correction chart. (Consider that the gear would obviously still be in the down position at lift-off).

H. Find the Equivalent Lift-Off Speed [KEAS] using your Calibrated Airspeed from G above and the Pressure Altitude for your selected airfield (from A). (Compressibility Correction Chart, see “Flight Theory and Aerodynamics”, Fig. 2.6). Comment on your findings in H. Why was/wasn’t the Compressibility Effect in your case negligible?

I. Find the True Lift-Off Speed [KTAS] (use the Density Ratio found in D). J. Calculate the Dynamic Pressure ‘q’ [lb/ft2], based on the TAS above. (Dynamic Pressure definition and formula can be reviewed in “Flight Theory and Aerodynamics” page 22; make sure to use a formula consistent with a Lift-Off Speed in kts).

Solution

It would be helpful If you Post charts and figures.