| F minor|
| E♭ major|
| A♭ minor
enharmonic: G♯ minor|
The A-flat major scale (A♭ major scale) consists of the pitches A♭, B♭, C, D♭, E♭, F, and G. Its key signature has four flats.
Its relative minor is F minor, and its parallel minor is A♭ minor, usually replaced by G♯ minor, since A♭ minor, which would contain seven flats, is not normally used. G♯ major, with eight sharps, including the F, has a similar problem, and so A♭ major is often used as the parallel major for G♯ minor. The same enharmonic situation occurs with the keys of D♭ major and C♯ minor, with C♯ major having seven sharps and D♭ minor having eight flats, including the B.
It was used quite often by Franz Schubert; twenty-four of Frédéric Chopin's piano pieces are in A-flat major, more than any other key.
A-flat major Wikipedia
Beethoven chose A-flat major as the key of the slow movement for most of his C minor works, a practice which Anton Bruckner imitated in his first two C minor symphonies and also Antonín Dvořák in his only C minor symphony.
Since A-flat major was not often chosen as the main key for orchestral works of the 18th century, passages or movements in the key often retained the timpani settings of the preceding movement. For example, Beethoven's Symphony No. 5 in C minor has the timpani set to C and G for the first movement. With hand tuned timpani, there is no time to retune the timpani to A-flat and E-flat for the slow second movement in A-flat; accordingly, the timpani in this movement are reserved for the passages in C major. In Bruckner's Symphony No. 1 in C minor, however, the timpani are retuned between the first movement in C minor and the following in A-flat major.
Charles-Marie Widor considered A-flat major to be the second best key for flute music.
A-flat major was the flattest major key to be used as the home key for the keyboard and piano sonatas of Domenico Scarlatti, Joseph Haydn and Ludwig van Beethoven, with each of them using the key for two sonatas: Scarlatti's K. 127 and K. 130, Haydn's Hob XVI 43 and 46, and Beethoven's Op. 26 and Op. 110, while Franz Schubert used it for one piano sonata. It was also the flattest major key to be used for the preludes and fugues in Johann Sebastian Bach's Well-Tempered Klavier, as flatter major keys were notated as their enharmonic equivalents.
Felix Mendelssohn, Johann Nepomuk Hummel, John Field, and Friedrich Kalkbrenner each wrote one piano concerto in A-flat (Mendelssohn's being for two pianos); they had the horns and trumpet tuned to E-flat. Max Bruch's Concerto for Two Pianos in A-flat minor has its last movement in A-flat major, which is the parallel major; this concerto plays with the contrast between the two keys.
Works for stringed instruments in this key include Antonín Dvořák's String Quartet No. 14 and Benjamin Godard's Violin Sonata No. 4.Franz Schubert – Impromptu op. 90 no.4 in A flat Major (Begins in A-flat minor)
Franz Schubert – Impromptu op. 142 no.2 in A flat Major
Franz Schubert – Moment Musical op. 94 no.2 in A flat Major
Franz Schubert – Moment Musical op. 94 no.6 in A flat Major (Ends with an A-flat minor context)
Arnold Bax – Symphony No. 7
Ludwig van Beethoven – Piano Sonata No. 31
Johannes Brahms – Waltz in A-flat major, Op. 39
Frédéric Chopin – "Heroic" Polonaise, Op. 53
Frédéric Chopin – Impromptu No. 1 in A flat major, Op. 29
Frédéric Chopin – Waltz in A-flat major, Op. 69, No. 1
Frédéric Chopin – Preludes, Op. 28, No. 17
Edward Elgar – Symphony No. 1 in A-flat major
Scott Joplin – "Maple Leaf Rag"
Franz Liszt – Liebestraum No. 3