Flying Machines 8 Tristar

A BA Tristar -200. The -200's can be recognised by the small fillet in front of the centre engine intake

A BA Tristar -200. The -200’s can be recognised by the small fillet in front of the centre engine intake

The Lockheed L1011 Tristar was the first aircraft I flew when I joined British Airways in 1989. By that time the Tristar 500s had all gone, so I never flew that legendary beast; my experience was limited to the -1 (later “improved” to -50 and -100) and the much better -200.

First a bit of history, the tristar was originally conceived as a short/medium haul wide body and the -1 model was bought by British European Airways (BEA) mainly for their high density routes (at first Paris and Athens). By the time the aircraft arrived BEA and BOAC had ceased to exist in name and had become British Airways (BA) and the Tristar had also developed into a long haul aeroplane as the -200.

This gave the new BA management a bit of a problem since BEA and BOAC were still alive and well having become BA European Division (BAED) and BA Overseas Division (BAOD) and the aeroplane would suit either’s routes. At this point BAED decided that as their new aircraft didn’t need inertial navigation equipment they would not only not have it fitted, but would (at extra cost) have the wiring removed during production thus denying the aircraft to BAOD operations in the future. The wiring and Inertial Reference Systems (IRS) were later replaced at considerable expense. In the end neither side really felt the Tristar was theirs and it was a bit of an un-loved duck for most of its service.

A Calledonian (really BA) Tristar, not as you might think taking off, but on final approach.

A Calledonian (really BA) Tristar, not as you might think taking off, but on final approach.

When British Caledonian Airways were taken over by BA, the former charter division (BEA Airtours, then BA Airtours) was renamed Caledonian Airways. The reason given was to “Keep the name alive”; many had suspicions that there must have been a lot of surplus “Cally” uniforms to use up. It was a very nice uniform.

The -1 aircraft were only really suitable for short haul routes until the undercarriages were replaced with a stronger version which increased the maximum take off weight (MATOW) by 20 tonnes; this was called the -50. Later the Caledonian Airways -50s were “paperwork moded” for another 20 tonne increase in MATOW. Since the engines were still the same as the -1 (which in any case was no-way overpowered) they suffered from a chronic lack of thrust which meant that a trans-atlantic -50 needed to have unrestricted climb from Heathrow to beyond the west coast of Ireland to get to 31000 ft (FL310). The even more sad -100 would often cross the Atlantic at FL240 because it couldn’t get any higher. At least there were less ATC problems at that level!

The -200 was a much better aircraft with bigger engines and happily reached Fl330 or FL350 to cross “the big pond”.

Two very non-BA crew in the UFG with the lifts visible behind. The UFG was the scene of many crew gatherings on long flights, not to mention rumours of assignations, but never proved!

Two very non-BA crew in the UFG with the lifts visible behind. The UFG was the scene of many crew gatherings on long flights, not to mention rumours of assignations, but never proved!

The original cabin configuration was to have all the catering and equipment stored in a large underfloor galley (UFG) with communication for food, equipment and people via two lifts towards the rear of the passenger cabin. In all but the Caledonian Airways aircraft this was later changed to main cabin galleys and the UFG turned into extra hold space.

So much for the BA history. The aircraft was built to a high standard and had few serious technical problems. The controls were light and effective (fully powered) and the Rolls-Royce RB211s were good, reliable engines, although not over endowed with thrust even for in those days. In a -50 at FL310 the engines stayed very close to climb thrust for most of the cruise. A very clever system that was active on the approach and landing was Direct Lift Control; this system deployed the spoilers by a few degrees when land flap was selected and if the elevators were moved would open or close to give direct control of lift with very little pitch change. This resulted in an almost constant power setting on the approach and very little pitch change in the flare for landing. The system worked well and was way ahead of its time.

The navigation system was a child of its times. The Flight Management System (FMS) had a very limited amount of memory and was, of course, analogue. This resulted in quite a lot of pilot input of data with the possibility of error. In those pre-GPS days the system relied on the IRS being updated by VOR and DME data to produce a FMS position. Over the Atlantic, with no other aids, the IRS was on its own and had errors of up to 15 miles by the time a landfall was made.

The autopilot was absolutely brilliant at doing an automatic landing. However, it was quite complicated and very inclined to disconnect if it didn’t like what it was asked to do at most other times. The auto thrust operated all three throttles by one servo motor which meant an eye had to be kept on the engines to check they were all staying together.

The Tristar had a few odd things about it. It suffered from a symptom know as “pod nod”; under certain conditions of light weight and mid speed at low altitude the wing engine pods would start to oscillate on their pylons in a circular motion clearly seen from the cockpit (and the cabin). This translated itself into a nodding motion of the whole aircraft. Lockheed claimed it wasn’t a problem, but with memories of the Electra crashes we avoided it as soon as encountered by changing speed. The caution “Hyd Rudder Limiter” would sometimes appear in the cruise and the problem was solved by turning off the logo light. No-one knew why these two entirely different systems should affect each other, but it was never-the-less in the check list.

 

TriStar Cockpit showing the Flight Engineers panel on the right and the two pilot's seats in front. This pic is clearly taken with all power off as there are warning flags on everything.

TriStar Cockpit showing the Flight Engineers panel on the right and the two pilot’s seats in front. This pic is clearly taken with all power off as there are warning flags on everything.