Airbus A320 series

Solar radiation and aircraft electronics: is this a big issue?

David Learmount Uncategorized , , , , , , , , , , , , , , , , , ,

Much of the world’s fleet of about 11,000 Airbus A320 series aircraft – the most popular airliner in the world according to sales – are affected by a current emergency airworthiness directive from the European Union Aviation Safety Agency and the US Federal Aviation Administration requiring that operators modify their aircraft control software to make it more resistant to the effects of solar radiation.

This followed a sudden loss of height in the cruise involving a JetBlue A320 en route from Cancun, Mexico to Newark, USA on 30 October. Solar radiation is believed to have been responsible for corrupting the data in one of the aircraft’s flight control computers causing the sudden height loss – which injured several passengers. Recovery action by the pilots ensured the aircraft diverted safely to Tampa, Florida.

Most younger A320s need only a quick software patch to harden the microchip resistance in their flight control computers against particularly vigorous bursts of solar radiation, but nearly a thousand of the oldest aircraft may need to change the units.

Solar radiation is known to be able to interfere with GPS signals, radio communication, inertial navigation systems, autopilot, and full-authority digital engine controls (FADEC), although incidents are rare. A mysterious sudden pitch-down by a Qantas A330 in the cruise over Western Australia in October 2008 is now reckoned to have been caused by corrupted data from an air data inertial reference unit (ADIRU) that may have been subject to solar radiation damage.

All aircraft are more vulnerable than suface vehicles to solar radiation effects because, at high altitude, there is less atmospheric attenuation of the sun’s electromagnetic energy. Polar flights are particularly vulnerable because the earth’s magnetic field provides less shielding and the troposphere is at a lower altitude there.

A320 series aircraft have three three flight control primary computers (FCPC), two flight control secondary computers (FCSC), and a flight augmentation computer, all of which provide considerable systems redundancy, plus a cross-checking capability to detect and correct anomalous data.

The UK Civil Aviation Authority said today that there had been virtually no disruption to flight schedules because airlines were so quick to apply software fixes.

1 December 2025: a statement from Airbus on this date claimed that only about 100 A320 series aircraft remained to receive the softwear hardening required by EASA an the FAA.

Boeing 737: the beginning of the end.

David Learmount Uncategorized , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

It hasn’t surprised anyone in the industry to hear rumours – via the pages of the Wall Street Journal – that Boeing is working on the design of a new narrowbody jet, because it’s what everyone – including Boeing – knows the manufacturer should have done instead of launching the 737 Max.

The confidence in that statement is completely un-influenced by hindsight.

Now the Max has been purged of the ghastly design mistake that was MCAS (manoeuvring characteristics augmentation system), and Boeing has radically overhauled its corporate safety culture under a new leader – former Rockwell Collins engineer CEO Kelly Ortberg – the 737 series can once again trade on the lazy confidence that comes from the fact that – with all its faults and its antique technology – it’s a known quantity.

As a result the 737 is selling well, but nothing like as well as its competitor the Airbus A320 series.

The first 737-100 entered service in 1968, initially to fly the routes that the larger 727 series trijet was too big for. Its basic control technology was – and still is – just-post-war, except that in the latest versions the power-assisted cranks and pulleys are overlaid with electronic flight instrument systems and flight management computers to the extent that the pilots could almost believe the aircraft is fly-by-wire. They know, however, that they themselves are the flight envelope protection.

The industry needs a new-technology narrowbody competitor to the A320, and if Boeing doesn’t supply it, perhaps a development of China’s Comac C919, Russia’s Sukhoi Superjet 100, or a new product from Brazil’s Embraer will fill the gap.

Boeing’s first fly-by-wire airliner was its highly successful 777 widebody, which entered service in 1995 with virtually no birthing pains.

In 2011 it launched the 787 Dreamliner series, also highly commercially successful, but suffering from multiple early problems, some of them still being worked on.

Right now Boeing is struggling to re-launch the 777 as the 777X. The fact that it had a planned 2019 in-service date, but now its launch customer – Lufthansa – will not receive it until 2026, suggests how difficult a task bringing an entirely new narrowbody (the 797?) to service readiness may yet be.

The challenge is always to deliver a safe, trouble-free product, but the staggeringly advanced, fully-integrated electronic technology by which the aircraft and all its systems will be managed and controlled, plus the fact that there must be fallback systems that the pilots can access easily if it all goes wrong, mean its service entry will not be quick.

Look beyond this to the fact that the new systems will inevitably employ artificial intelligence, which makes passengers – and even engineers – nervous when it comes to managing safety-critical systems, and the size of the challenge becomes clear.

So the venerable 737 series will be with us for many years yet.