The weekly rollerboard 19 January: A350 special
The A350XWB flight test campaign continues in earnest, and with more than 850 flight hours now logged it’s time I wrote an update. I was following the campaign and the CSeries more closely in the initial stages, but the number of great resources available online meant I took a bit of back seat.
The static test frame MSN5000 has now successfully completed ultimate wing load testing reaching a five metre deflection the wing, subjecting the wing to loads to 1.5 times greater than expected in service life. Strains were measured by 10,000 measurement channels which correlate load information against structural design models.
The ultimate load is the beyond which the wing is expected to fail, and is calculated at 2.5 times the maximum expected G load. As the Airbus Fly By Wire system limits G loads to +2.5G or +3.5G in a reversion to Direct Law, the ultimate load could be higher than 7.5G.
For the first time Airbus didn’t stress the wing to its load failure point – the moment at which the wing breaks. Composites shatter rather than break in an unpredictable way as the fibrous matrix carries multiple load paths; unlike comparable metal wings if both wings failed and were then analysed there would be no common characteristics between the two that indicated tension load was the cause of the failure. Also, as composites shatter they release needle-sharp fibres presenting a challenging cleanup. So the actual failure load may never be known.
High as a kite.
The second test A350 MSN3 has completed completed high altitude testing at the Bolivian airports Cochabamba (8,300 ft AMSL) and La Paz (13,300ft AMSL).
Operations at this altitude are particularly straining on the aircrafts engines, APU and environmental control systems. Test flights assessed takeoff and landing performance, as well as engine and handling performance during simulated engine failures events on takeoff. In addition, the flights validated autopilot performance at high altitude, oxygen systems and avionics ventilation.
Airbus is seeking regulatory approval for ETOPS (Extended Twin Engine Operations or Engines Turn Or Passengers Swim) 420 operations, which would allow the A350 to fly up to seven hours from an aerodrome on one engine.
Currently the 777 with GE engines has ETOPS 330 approval, the A330 ETOPS 240, while the the Boeing 787 remains restricted to ETOPS 180.
There is no trans-polar or oceanic route in the northern hemisphere that requires more than ETOPS 240 approval, so Airbus’ application for ETOPS 420 would only open up new possibilities down south. The only practical application of 420 minute ETOPS would for polar operations over Antarctica, and that really only opens up a handful of routes. Of these only one – Auckland to Johannesburg – has commercial imperative the others all rely substantially on hub traffic. That commercial imperative may change over the next 20 years, and while there is jet capable runways in Antarctica, it’s unlikely the CASA or the FAA would approve operations so far from fields that could not support emergency landing requirements.
I’ve got some pretty cool models at home, but this is genuinely incredible. Luca Iaconi-Stewart, an architecture student and #avgeek, has built a 1:60 scale model of an Air India 777-300ER made entirely of manila folders. But there’s a level of fastidiousness that goes further than just gluing together some paper together. Iaconi-Stewart’s model incorporates functional doors, latching mechanisms, a full retraceable landing gear, thrust reversers all built with hands and tweezers. For parents looking to teach their kids how to make a paper aeroplane, the bar has just been lifted a notch.
*updated 19 January to correct mistaken reference to A350 static test frame as MSN500 rather than MSN5000.