Tandem



Tandem (or in tandem) is an arrangement where a team of machines, animals or people are lined up one behind another, all facing in the same direction.

Tandem harness (the original use of the term in English) is used for two or more draft horses (or other draft animals) harnessed in a single line one behind another, as opposed to a pair, harnessed side-by-side, or a team of several pairs. Tandem harness allows additional animals to provide pulling power for a vehicle designed for a single animal.

Tandem seating may be used in two-seat aircraft, or on a tandem bicycle where it is alternative to sociable'' seating.

The English word "tandem" derives from the Latin adverb tandem meaning "at length" or "finally".

The term "tandem" can also be used more generally to refer to any group of persons or objects working together, not necessarily in line. A tandem arrangement may also be used for cars parked in a garage.

Aviation
The two seating configurations for trainer aircraft are pilot and instructor side by side or in tandem, usually with the pilot in front and the instructor behind. A cockpit can be lengthened to create a trainer with tandem seating from a single seater aircraft.

Side-by-side seating
An alternative configuration is side-by-side seating which is common in large aircraft but less so in high performance jets. The Grumman A-6 Intruder, General Dynamics F-111 or the Sukhoi Su-24 are examples of combat aircraft which use this configuration. For training aircraft, it has the advantage that pilot and instructor can see each others' actions, allowing the pilot to learn from the instructor and the instructor to correct the student pilot. The tandem configuration has the advantage of being closer to the normal working environment that a fast jet pilot is likely to encounter.

In some cases such as the EA-6B Prowler, a two-place aircraft can be modified to be made longer into a four-place aircraft. Also a single seat cockpit can be redesigned into a side-by-side arrangement in the case of the A-1 Skyraider, TF-102 trainer or the Hawker Hunter training versions.