To simplify the expression \( 4^x - 14 \) when \( x = 5 \), we first substitute \( x \) with 5:
\[ 4^5 - 14 \]
Next, we calculate \( 4^5 \):
\[ 4^5 = 4 \times 4 \times 4 \times 4 \times 4 \]
Calculating step by step:
\[ 4 \times 4 = 16, \]
\[ 16 \times 4 = 64, \]
\[ 64 \times 4 = 256, \]
\[ 256 \times 4 = 1024. \]
So, \( 4^5 = 1024 \).
Now we can substitute this value back into the expression:
\[ 1024 - 14 = 1010. \]
Thus, the simplified result of the equation \( 4^x - 14 \) when \( x = 5 \) is:
\[ \boxed{1010}. \]