Air Observation Post (AOP) is an aeroplane used in the role of artillery spotter by the British Army and Commonwealth forces.
The Auster AOP.6 (Auster Model K) was designed as a successor to the Taylorcraft Auster V, it had a strengthened fuselage, increased all-up weight and a 145 hp (108 kW) de Havilland Gipsy Major 7 engine.
It had a different appearance to the wartime Auster’s due to the lengthened landing gear struts (due to the larger propeller), and external non-retractable aerofoil flaps.
An initial production run of 296 were completed for the Royal Air Force in 1949.
A second batch was produced from 1952 with a total delivered of around 400.
Some aircraft ordered by the Royal Air Force aircraft were diverted to the Belgian Air Force and the Royal Hong Kong Auxiliary Air Force.
New aircraft were delivered to Royal Canadian Air Force, South African Air Force, and the Arab Legion Air Force (Jordan).
A dual-control training version of the AOP.6 was produced, 77 serving as the Auster T.7 (Auster Model Q).
These flew alongside the AOP.6 in the AOP squadrons.
In 1955 two T.7 aircraft were modified for use on the 1956 Commonwealth Trans-Antarctic Expedition, being designated Auster Antarctic (Auster Model C4).
The aircraft had extra radio equipment, larger tail surfaces, the ability to be fitted with floats or skis as required and a bright yellow finish to increase visibility against the snow and ice.
The aircraft was gradually replaced with the Auster AOP.9 from 1955 and surplus aircraft were converted to civilian use, first as the Auster 6A and later as the Beagle A.61 Terrier.
Variants
Production
Model K – Auster AOP.6
Production aircraft, 378 built
Model Q – Auster T.7
Dual-control training variant of the AOP.6, 84 built.
Auster AOP.8
Proposed three-seat AOP variant of the T.7, not built.
Conversions
Auster T.7 Antarctic
Two T.7s converted for use in the 1956 Commonwealth Trans-Antarctic Expedition.
Auster T.10
AOP.6s converted to T7 standard, 10 conversions.
Auster 6A Tugmaster
Former military aircraft converted for use as a civil glider tug.
Beagle A.61 Terrier
Former military aircraft converted for civil use.
Marshalls MA.4
An Auster T7 modified by Marshalls of Cambridge with a new wing and larger tailplane.
Perforations in the wing, ailerons and flaps were connected to a suction pump driven by an auxiliary gas turbine engine in the fuselage.
The aircraft was used for research into boundary layer control.
The sole example, Serial VF665, lost control and crashed on 8 March 1966 in Suffolk, killing both crew.
Specifications
Crew
3
Length
22 ft 5 in (6.83 m)
Wingspan
36 ft 0 in (10.97 m)
Height
8 ft 0 in (2.44 m)
Wing area
167 sq ft (15.51 m2)
Empty weight
1,100 lb (499 kg)
Max take-off weight
1,850 lb (839 kg)
Powerplant
1 × Lycoming O-290-3 flat-four piston, 130 hp (97 kW)
Performance
Maximum speed
113 kn (130 mph, 209 km/h)
Stall speed
28 kn (32 mph, 51 km/h)
Range
220 nmi (250 mi, 402 km) 400 nmi with long range tank fitted.
