Britain's Dreadnought-class missile submarines will use fly-by-wire

Britain's Dreadnought-class mi...
Artist's concept of HMS Dreadnought
Artist's concept of HMS Dreadnought
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Artist's concept of HMS Dreadnought
Artist's concept of HMS Dreadnought

When the first of the Royal Navy's Dreadnought-class nuclear missile submarines takes to the sea late in this decade, it will be steered by the same fly-by-wire technology used in aircraft. Called the Active Vehicle Control Management (AVCM) system, it will control all the major facets of the giant boat's maneuvering.

At first, there doesn't seem to be much in common between a Typhoon fighter jet and a 17,200-tonne nuclear-powered submarine stuffed with Trident missiles. Obviously, the two are designed for very different purposes and operate in very different environments that often make them polar opposites. This is why flying submarines remain the inhabitants of bad science fiction.

However, submarines and planes are very similar in one important aspect. Both, in a sense, fly. True, one operates in the air and the other underwater, but the way air and water flow over a vehicle is very similar in a surprising number of ways. In fact, many submarine hull designs are based on the aerodynamics of airships and how a sub's control systems work is very like those of an aircraft.

Therefore, it isn't surprising that BAE Systems engineers thought of taking avionics and adapting them to the Dreadnought-class boats. When fully functional, the AVCM system will use computers to oversee the vessel's heading, pitch, depth, buoyancy, and other aspects while making sure it remains within a safe performance envelope.

Based on the Astute attack submarine, the four Dreadnought-class submarines will replace Britain's aging Vanguard-class Trident submarine when they enter service sometime after 2030. Each will be powered by a Rolls-Royce PWR3 nuclear reactor, which will never need refueling during the submarine's service life into the 2050s. They will carry up to 12 US-built Trident D5 missiles in the US/UK Common Missile Compartment, each armed with multiple British designed and built nuclear warheads on MIRVs (Multiple Independently targetable Re-entry Vehicles).

"With over 50 years of avionics experience, we already have a great understanding of how to develop complex, control systems for hi-tech platforms," says Jon Tucker, Director for Maritime Controls at BAE Systems Controls and Avionics. "However, taking our technology underwater brings exciting new challenges, and we are proud to support the Dreadnought program and play an important part in our national security effort."

Source: BAE Systems

Yes! Like everyone else we're putting all our eggs in a known fragile basket with no mechanical back-up!

What could possibly go wrong?
There's a massive difference between the environment in an airplane and a seagoing craft. They better be ready with a plan B when this thing doesn't work out right.
''Sorry chaps, the computer has a glitch! We're stuck on the bottom until we can find the problem, and fix it, maybe.''
Or, alternatively, ''Oh shi.! Due to a faulty switch, the computer has just fired all our torpedoes and...!
At least in a military aircraft, if there is a drastic fail, and it happens far more times than ever reaches the newspapers, the pilot and crew can eject/bale out. At ''20,000 leagues under....''NOPE!
Kevin Schmidt
Perhaps BAE should take the advice of the armchair engineers below and install noisy gears, levers, and control shafts. Most car throttles are fly-by-wire, as are almost all new airlines. Redundancy, and dispersion of these redundant systems is what adds reliability. Perhaps some would prefer we use WW2 technology to face our foes?
Dennis Taylor
Isn't it time to do away with "fly-by-wire" terminology? That was unique in the 80's or 90's when if first came to the fore. Today, virtually every device or machine has some sort of sensor/control circuit that is not a mechanically-coupled system as in days of yore. And, yes, as noted in several other comments, back-up or fail-safe systems are necessary, ESPECIALLY in submarines.
In many science fiction films, the space ships are always equipped with escape modules. Do modern subs have the same?
If not, Why Not?
Kevin Schmidt
Worzel, escape pods are standard equipment on the Finkleberg class fast attack subs. They have enough capacity to carry all assigned sailors minus one. The captain is expected to go down with his ship, and his cabin is stocked with a small vial of brandy for him to enjoy as he contemplates his last moments, while steel creaks and the lights flicker.
Baker Steve
Hmm... If I were a submarine commander, I'm not sure how happy I'd feel with a control system that 'makes sure [the sub] remains within a safe performance envelope'. Submarine warfare is all about cunning, agility and surprise, not about arguing with control systems that think they know best but can do unexpected things at crucial moments, as a study of civil aviation disasters can illustrate.

I am unsure how much of Kevin Schmitd's tongue is in his cheek, but the issue with all such systems is the software, which is horribly, horribly difficult – maybe impossible – to get absolutely right. Within the expected performance envelope, fine, but when things go awry, those operating such systems can be overwhelmed with warning messages, autonomous behaviour and control systems decoupling because they can't understand what's going on.

I worked on such for a company that was subsequently bought by BAe Systems, and later worked for the latter.