It captured the public’s imagination, and the aviation industry had never seen anything like it. Some would argue that nothing has come close since.
It was on 2 March 1969 that Concorde had its maiden test flight, taking off from Toulouse airport and spending 27 minutes in the air before being brought safely back to ground. “Finally the big bird flies, and I can say now that it flies pretty well,” pilot Andre Turcat is reported to have said.
The following month, Concorde had a 22-minute test flight, leaving Filton, near Bristol, and touching down at RAF Fairford, roughly 50 miles away. But it wasn’t until 21 January 1976 that the aircraft entered commercial service when British Airways made a journey from London to Bahrain and Air France flew from Paris to Rio.
Fifty years on from Concorde first gracing the skies, commercial supersonic flight is yet to roar back into existence. Because, as much as the aircraft was a marvel, it was also a magnificent feat of engineering, albeit one plagued with problems over the course of its lifetime.
To coincide with the 50th anniversary of the maiden flight, engineers who worked on Concorde during some of the aircraft’s tumultuous periods share their experiences.
On 12 April 1989, G-BOAF, one of several commercial Concordes produced in the UK, lost part of its upper rudder while flying between Christchurch, New Zealand, and Sydney. This was the first of five reported rudder failures that Concorde aircraft would experience over the next decade-and-a-half. The next one was on 4 January 1991, when part of an upper rudder separated during a flight from London to New York.
Crawford Murray, who worked on the rudder repairs carried out during the early to mid-1990s, recalls why the incidents were occurring. “The rudders were originally designed with a one-inch snub trailing-edge design, and, in order to improve performance, a wedge was added quite early on, which was riveted onto the existing structure. Unfortunately, these rivets created a water ingress path and this resulted in extensive corrosion along the trailing edge of all of the rudders.”
The moisture that had entered the bonded structure of the rudders had corroded the honeycomb structure. The repairs involved cutting away the damaged sections and bonding in new honeycomb structure and skins.
“The challenge was to ensure the original profiles were maintained and that the bond lines were correct. This involved developing bond line checks using adhesive between layers of release film to make sure that the honeycomb was not undulating,” explains Murray.
While part of an aircraft breaking off sounds terrifying to any passenger, in actual fact Concorde could fly successfully with just the one rudder. Former pilot Jock Lowe has previously said that rudders were only really needed in exceptional circumstances, such as for steering during take-off and if there was an engine failure or the aircraft was flying into cross-winds.
An appreciation for design
Another interesting repair that Murray was involved in was to fix cracking on the rear intake ramp frames. “Given the complex machining on the frame and the location of the cracks in the frame corners, analysing the repair was quite a lengthy and complicated task,” he says.
Having carried out a lot of repair work on the intakes, Murray quickly began to appreciate the engineering genius of those who designed and built the aircraft.
“It amazed me how the original design team came up with the concept of taking supersonic flow and reducing it so it entered the engines at the correct speed, while also ensuring that the engines were aligned correctly with the intakes,” he says. “This isn’t at all easy given the fact that they weren’t connected and the wing deflections had to be compensated for. The mechanism the design team came up with was truly inspired and worked perfectly.”
When not to repair
Sometimes decisions engineers made about what not to do were also highly important.
“One of my best non-repairs was to leave a 16ft-long gouge in the tail section of the G-BOAC aircraft,” says Murray. “The gouge was in the fuel tank’s skin structure. Trying to design a flush repair proved tricky and in the end I decided it was best left as it was. After all, any cracks would quickly have been evident and, also, repairing it would have left the structure much weaker than it already was.”
Extending the service life
In 1998, BA contracted BAE Systems to conduct a study into whether Concorde’s service life could be extended by a further 15 years. Nick Schulkins was part of the non-advocate review, working for a company contracted by Rolls-Royce to study the engine, air intake, and the reheat and thrust reverser systems. The aim of the study was to perform reliability analysis from the flight line to the engine overhaul facility in Treforest in South Wales.
“During the study, we concluded that the engine, an Olympus 593, wasn’t supportable beyond about five years. The main reason for this was that the Olympus repair shop in Treforest had 110 staff, and, of these, about half were due to retire within five years. Plus, there was only one apprentice,” recounts Schulkins.
“The engine was difficult to maintain and involved more skill of hand than modern aircraft engines, and spare parts were hard to source and support costs were high,” he continues. “When looking at the Concorde fleet’s maintenance practices, we also found some of them to be inadequate. We found sloppiness and over-confidence, which, in my experience, eventually leads to an accident.”
According to Schulkins, the findings in his employer’s report upset BA and the airline’s engineering director was reported to have told Rolls-Royce that it shouldn’t use his employer again.
“The same individual was later quoting from our report when Air France had its fatal accident in Paris. Clearly our recommendation that the engine was unsupportable was not what BA had wanted to hear, but we believe Rolls-Royce was content with what we had found.”
Parts two and three of our feature Remembering Concorde, on the end of the era and a potential supersonic comeback, will be published on Thursday and Friday (28 February and 1 March).
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.