  Interleaved Reed-Solomon codes admit efficient decoding algorithms which
correct burst errors far beyond half the minimum distance in the random errors
regime, e.g., by computing a common solution to the Key Equation for each
Reed-Solomon code, as described by Schmidt et al. If this decoder does not
succeed, it may either fail to return a codeword or miscorrect to an incorrect
codeword, and good upper bounds on the fraction of error matrices for which
these events occur are known. The decoding algorithm immediately applies to
interleaved alternant codes as well, i.e., the subfield subcodes of interleaved
Reed-Solomon codes, but the fraction of decodable error matrices differs, since
the error is now restricted to a subfield. In this paper, we present new
general lower and upper bounds on the fraction of error matrices decodable by
Schmidt et al.'s decoding algorithm, thereby making it the only decoding
algorithm for interleaved alternant codes for which such bounds are known.
