Test Data

Aircraft at 631 VGS

631 VGS like many other squadrons has had its share of aircraft over the years. From the Dagling to the MkIII to the T21 (Sedburgh). Then on to the ASK21 (Vanguard), the Grob 103 (Viking) and now, the Grob 109b (Vigilant).

Aircraft Integrity

On a day to day basis, a minimum of seventeen signatures are required from suitably qualified instructors before any aircraft can be flown. These signatures state the aircraft are fit for flight.

All instructors and graded pilots can be authorised to carry out some servicing depending on their grade or instructor category. Generally, the higher the category the more the instructor can do.

These suitably qualified instructors and graded pilots, are authorised to carry out basic servicing to the aircraft, and to check our parachutes. General multipoint checks are carried out each flying day to make certain each aircraft is fit to fly. At the end of the days flying, further checks are carried out to determine if the aircraft have sustained any minor damage, such as stone chips to the gel coat, with definitive multipoint checks also carried out. All this is done in accordance with instructions from higher authority and after comprehensive training. Further checks are carried out once every seven days to ensure there is enough oil and hydraulic fluid, plus, general engine checks together with fuel contamination and tyre pressure and condition checks.


The Vigilant four cylinder horizontally opposed air cooled 2500 E1 piston engine develops approximately 95bhp at 2,950rpm. It is a dual control, training light aircraft which can quickly be converted to glider mode, it is in fact a motor glider. However, when in the mood, it can condescend to flying a little faster than the word "glider" suggests. It will cruise quite comfortably at 90 knots (approx 103mph) for 5-6 hours. It has a max speed of 130 knots, depending on weight and altitude. It has a ceiling of 8,000ft. In normal training mode we fly the aircraft at 60 knots.

It is a low-wing cantilever machine, with a T-tail, folding (and detachable) wings, and side-by-side seating with dual controls. It is mainly constructed from glass-reinforced plastic and has a "tail-dragger" undercarriage arrangement. Entry and exit from the cockpit is via two perspex doors which open upwards individually − a modification from the original one-piece G109 canopy. The cockpit can be heated, providing that the engine is running, and the seat backs can be adjusted and cushions of differing thickness inserted to accommodate a range of body sizes.

Summary of Characteristics

Crew : Two (student and instructor)
Length : 8.10m (26.57ft)
Wingspan : 17.4m (57.09ft)
Height : 1.7m (5.58ft)
Wing Area : 19.0m2 (204.5ft2)
Empty Weight : 620kg (1,364lb)
Loaded Weight : 850kg (1,874lb)
Max. Takeoff Weight : 908kg (2,001lb)
Powerplant : 1x Grob 2500 4-cylinder air-cooled piston engine, 95hp (71kW)
Wing Loading : 47.8kg/m2 (9.79lb/ft2)
VNE (Never exceed speed) : Up to 850kg: 130kts (below 6,500ft)
Above 850kg: 121kts
Service Ceiling : FL80 (approx. 8,000ft, 2,438m)