Complex sentence: On 13 July two B.E.2.e aircraft took off for a photography patrol but their escort failed to meet them over Esani, subsequently one aircraft was shot down killing the pilot and observer, while the other aircraft landed safely back behind EEF lines.
Split into simpler sentences: On 13 July, two B.E.2.e aircraft took off for a photography patrol, but their escort failed to meet them over Esani. Subsequently one aircraft was shot down, killing the pilot and observer, while the other aircraft landed safely back behind EEF lines.