The cockpit is very well laid out. The instrument panel consists of three easily removable, padded boxes, the one in front of the pilot carrying all the primary flight instruments and a very comp rehensive annunciator panel. The one on the right contains the power gauges and some additional flight instruments, and the centre one houses a large vertical stack crammed with avionics and topped with vertical-reading gauges showing engine oil pressure and temperature, volts and fuel quantity. The avionics suite includes a Honeywell KMD 550 MFDS with colour GPS and a KFC 225 autopilot and flight director. Note the large stepped panel for the circuit breakers to the left of the pilot, the comprehensive annunciator panel above the flight instruments and the useful grab handle located under the panel. The large red knob under the instrument panel is for emergency undercarriage extension.

Today's Pilot Jan 2001), I was interested to see how many differences I could spot and whether or not Socata had implemented any further improvements (apart, of course, from fitting a turbocharged engine) to what was already a very well thought-out aeroplane. I particularly remember that the TB20's baggage bay door was perhaps not as large as it could have been. Therefore I was pleased to note that on the TB21 (and later model TB20s) the height of the door has been increased by eight inches.

The actual baggage capacity remains usefully high at 143lb. Other improvements were that the cabin is now five inches taller and boasts a new interior, and that the wingtips have been redesigned.

As I'd noted the last time that I'd flown a Socata-built aircraft, build quality is very good. Wherever possible the aeroplane's skin has been flush-riveted (which helps to reduce drag), while the windows are also flush-mounted. A carbon-fibre honeycomb sandwich is used to make the fuselage's upper panels and, interestingly, a CNC (computer numerically controlled) milling machine produces the main spar from a single piece of metal. This means that the wing's single spar has no joins at all, which makes it very strong wing, as any homogenous structure is inherently stronger than a modular structure. As on the TB20, the fin and rudder is set forward of the stabilator and a similar pair of ventral strakes are mounted under the fuselage.

The main undercarriage legs are of the superior trailing link design. An electro-hydraulic pack is used to retract the undercarriage and, unusually, there are no mechanical up-locks. The wheels are retained in their wells solely by hydraulic pressure. Should the electro-hydraulic pack fail, the pilot merely releases the hydraulic pressure by actuating the emergency undercarriage lowering system. Springs then assist the undercarriage to free-fall into the extended position.

Entry to the spacious cockpit is first-class. Small steps (which retract when the undercarriage retracts) are mounted either side of the fuselage just aft of the trailing edge, making it easy to step up onto the wing and then down into the cockpit. As on the TB20, I was pleased to note that the non-slip wing root walkway is of a decent size. Too many aircraft have unreasonably narrow wing root walkways, making it only too easy for someone to walk where they shouldn't. Once in the cockpit my initial impression was that the cabin really does seem large for an aircraft in this class. The cabin is just over 50 inches wide and almost as tall, while the large windows give the cockpit a bright, airy feel. As with the TB20, the rear seat is of the bench type and is certified for three occupants. This bench seat is easily removed for carrying over-sized cargo up to 550lb.

I thought the pilot's seat was extremely comfortable. A useful grab handle located under the panel makes it easy to pull yourself forward in the seat and the range over which it can be adjusted is generous. Inertia-reel seat belts are fitted as standard and the rudder pedals also adjust. If you cannot get comfortable
in this cockpit, it's your own fault!

The panel is of an unusual but very practical design. It consists of three easily removable, padded boxes, with the one in front of the pilot carrying all the primary flight instruments and also a very comprehensive annunciator panel. The one on the right contains the power gauges and some additional flight instruments, and the centre one houses a large vertical stack crammed with avionics. As on the other aircraft in the TB range, the centre stack is topped with vertical-reading gauges that show engine oil pressure and temperature, volts and fuel quantity. As you'd expect on an aircraft in this class, the avionics suite is very comprehensive and for 2002 includes a Honeywell KMD 550 MFDS with colour GPS and a KFC 225 autopilot and flight director. And what makes the panel design practical? Well, both the left and right hand boxes 'tilt out', making for easy maintenance.

At the base of the avionics stack is a sizeable centre console that carries the throttle, prop and mixture levers, elevator trim wheel and adjacent pitch trim indicator, cigar lighter (which also functions as a 24-volt power point) and ashtray, as well as a knob for the rudder trim and markings to indicate rudder trim position. There is a rocker switch for the electric pitch trim on the pilot's yoke, which also incorporates buttons for the PTT and autopilot disconnect. Further back on the console is the rotary fuel tank selector, while immediately in front of the power control levers is a flat panel that carries a guarded pre-select switch for the flaps, a flap position indicator and the buttons for the electrics.

The system used for selecting the electrical services is worthy of comment, as Socata favours the use of thermal overload buttons. Consequently, each service has two push buttons a green one for 'on' and a red one for 'off', while the circuit breakers are located in a neat stepped panel next to the pilot's left knee.

One feature that I really approved of was that an electric fan supplements ram air for supplying fresh air to the cabin and de-mister, as on any car. Why don't more aeroplanes have this very useful device? Your guess is as good as mine! I liked the cockpit a lot. It is comfortable with good ergonomics and also has some very useful stowage areas for the Pilot's Operating Handbook, Airways manuals, flight guides, etc. In fact, my only real quibbles would be the lack of a DV panel and that the altimeter is of the old three-pointer design. As this aircraft is designed to cruise at 25,000 feet it really should have a drum-type altimeter with a single pointer.

The engine started readily and I was soon wending my way towards the active runway. The nosewheel steers through the rudder pedals, although differential braking can be used to reduce the turning circle.

With four people on board and full fuel tanks we were just about on the maximum take-off weight, and I was curious to see how the TB21 would perform on a hot day with nil wind. Having checked the mags, cycled the constant speed prop, adjusted the elevator and rudder trims to the 'take off' settings, turned the fuel pump 'on' and set the flaps to 10°, I rolled out onto the runway and smoothly opened the big Lycoming up to full power.

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