Changes needed for the melodic and harmonic versions of the scale are written in with accidentals as necessary. The A-flat harmonic minor and melodic minor scales are:
Although A-flat minor occurs in modulation in works in other keys, it is only rarely used as the principal key of a piece of music. Some well-known uses of the key in classical and romantic music include:
An early section of the last movement of Beethoven's Piano Sonata No. 31, Op. 110 (although the key signature of this section uses only 6 flats, not 7).
The second Trio in Franz Schubert's Klavierstücke in E-flat major for Piano, D946/2.
Schubert's Impromptu in A♭ major actually begins in A♭ minor, though this is written as A♭ major with accidentals.
The second movement of Ferdinand Ries' Concerto No. 2 for Piano and Orchestra in E-flat Major, also written as A♭ major with accidentals.
In Gustav Mahler's Ninth Symphony, there is a particularly aggressive restatement of the introduction of the third movement in A-flat minor.[1]
The first movement of Charles Koechlin's Partita for Chamber Orchestra, Op. 205, is in A-flat minor, and the earlier A-flat-minor portion is written with a 7-flat key signature, but the later A-flat-minor portion is written without any key signature, and uses the necessary flats as accidentals.[2]
It is also used in Frederick Loewe's score to the 1956 musical play My Fair Lady; the Second Servants' Chorus is set in A-flat minor (the preceding and following choruses being a semitone lower and higher respectively).
More often, pieces in a minor mode that have A-flat's pitch as tonic are notated in the enharmonic key, G-sharp minor, because that key has just five sharps as opposed to the seven flats of A-flat minor.
In some scores, the A-flat minor key signature in the bass clef is written with the flat for the F on the second line from the top.[nb 1]
Notes
^An example of this is the bass clef staff of the harp parts in the Jupiter movement of Gustav Holst's orchestral suite The Planets.[3]
References
^Mahler, Gustav. Symphony No. 9 in Full Score, Dover, ISBN0-486-27492-6 (1993), pp. 116–119.