Problem #2

I went out this morning to 19th street to fulfill one of the requirements as described in Sub Part F of 14 CFR 61.129.h.11.c.  Given all the facts stated below why could I not complete the described task?

Flight service report at 6:30 AM

Temp 46 dew point 35

overcast

visibility 10 miles

winds calm

weather to remain the same for the next few hours

All equipment is in proper working order and crew available and the pilot is go to go. 

Answer #2

The formula for calculating the approximate base of the formed clouds is Cloud Base Altitude = ((((temperature - dew point) / 4.5) * 1000) + measure station altitude). As a mass of air rises, particularly on warm and humid days, it expands in the lowering air pressure, causing the air mass to cool and greatly reducing the air's ability to hold moisture. At some point, the moisture in the air exceeds the value which that air mass can hold, forcing the water vapor to condense, forming clouds. The point at which when air is cooled to the temperature that it can no longer hold its moisture is called the dew point. The rate at which air cools as it rises is averaged at 5.5°F per 1000 feet; the variable is the speed of the rising air mass. The dew point also decreases at about 1.0°F over the same distance. Thus the spread between the air temperature and dew point decreases by 4.5°F per 1000 feet. The altitude at which this spread becomes zero can be calculated using the stated formula. 

Given: 19th street is 5100 feet MSL (Check your sectional)

base of clouds is (agl) (46-35)/4.5 * 1000

base of clouds is (agl) (11))/4.5 * 1000

base of clouds is (agl) 2.44 * 1000

base of clouds is (agl) 2,440  feet

or 5100 plus 2440 = 7540 MSL

In summary 61.129.h.ii) For a balloon with an airborne heater

(A) Two training flights of 1 hour each in a balloon with an airborne heater on the areas of operation appropriate to a balloon with an airborne heater within 60 days prior to application for the rating;

(B) Two solo flights in a balloon with an airborne heater on the appropriate areas of operation; and

(C) One flight involving a controlled ascent to 3,000 feet above the launch site.

I would be flying ion Class E airspace where the distance from clouds is 500 below, 1000 above and 2,000 to the sides.  But the issue is I cannot ascend to 8,100 to fulfill the requirement as the clouds are there and I need to stay a least 500 below them or the highest I go ascend is 7,040.