[3] These crashes were found to be the result of structural deficiencies, which required substantial redesign, particularly of the center-section wing spars.

[3] These were a radical departure from their increasingly obsolete predecessors, the G.3 and G.4, both of which were pod and boom designs, and were difficult to defend due to the positions of the crew.

[3] Its unimpressive climb rate and poor ceiling resulted in a few aircraft being tested with more powerful 150 hp (110 kW) Hispano-Suiza 8Aa engines.

Development delays meant the first aircraft didn't reach the front lines until late 1916, so that only one example was in service at the start of October.

In early use Escadrille C.46 had claimed 34 German aircraft brought down with its R.4s in an eight-week period, but it was clear that an improved ceiling and greater manoeuvrability were necessary.