Air-display safety parameters are rigidly enforced at Farnborough.

David Learmount/LONDON

SUKHOI'S SU-37 THRUST-vectored fighter provided the 1996 Farnborough air show with its most stunning flight display, involving the "Kulbit", or somersault, manoeuvre. The routine, however, had to be revalidated by the show organisers twice during the week because of unintentional "busts" through height or display-line limits.

The McDonnell Douglas (MDC) F-18 was not displayed throughout the week because, on the third day, it recovered from a tight manoeuvre well below the 500ft (150m) permitted minimum. The pilot was banned and, since MDC had not brought a standby F-18 pilot, the aircraft was flown back to the USA.

Farnborough's mercilessly applied display limits, because it is a military base, are derived from Joint Services Publication 318 rules. These are policed at Farnborough by the Society of British Aerospace Companies (SBAC) Flying Control Committee, headed by Grp Capt Roger Beasley. Approved minima take into account that many aircraft are displayed at the edges of performance envelopes and all are close to show crowds. Minimum-approved-height above ground level (AGL) varies according to the type of aircraft: for example, helicopter limits are different from those for fixed-wing jets. For the latter, 500ft AGL "-is standard", says the UK Civil Aviation Authority's head of general aviation, Alan Daley, who is responsible for safety of displays at civil airfields. Also forbidden is flight over the crowd or "busting" the display line in front of the spectators. All displays have to be validated individually before the show by the SBAC's committee.

As display sites go, Farnborough is not ideal. The Royal Air Force's formation aerobatic team, the Red Arrows, categorises it as unacceptable for display flying, but special dispensation to display there is given because of the air show's industrial importance and the site's historical association with UK aviation.

The RAF team is allowed to fly its British Aerospace Hawk 60s much lower than are the pilots of most other display aircraft, because the aircraft are not taken anywhere near the edge of their performance envelopes during the display. Also, other pilots displaying aircraft tend to be test or squadron pilots first, and display pilots second, unlike those of the Arrows.

Source: Flight International