The "A" Model

There's an old saying in aviation that goes "Never fly the 'A' model of anything!" It neatly encapsulates the conservatism and resistance to change that, whether through innate personality, training, or experience, is an enduring trait of professional aviators. There's also the hard fact that a number of new aircraft designs over the years had hidden flaws that became apparent only after a fatal crash or two. Much more commonly, the bugs aren't serious enough to cause an accident, but cost early-adopting operators considerable time, money, and operational reliability while they work through the teething stage. This was the case with Horizon when they were the launch customer for the Q400, and with the JungleBus when jetBlue, USAir, and Republic took their first deliveries (At jetBlue, it was popularly known as the E180...because you'd always make a "180" back to the gate!).

On Thursday, a Qantas A380 suffered an engine failure six minutes after takeoff from Singapore's Changi Airport enroute to Sydney. Although modern engine failures are quite rare, they do happen, and they're not always indicative of a design or widespread manufacturing flaw. Even in a new design like the A380, an inflight engine shutdown would likely attract little interest outside of Qantas, Airbus, and Rolls-Royce.

This engine, however, failed in a very violent fashion, essentially blowing itself apart - a rare event known as catastrophic failure. When any such failure does happen, it most typically originates in the fan stage. For this reason, cowlings are built extraordinarily strong in the area around the fan blades, and engine manufacturers conduct rather spectacular tests to ensure they are sufficient to contain any catastrophic failure. You can see the "Blade Off" test for the A380's Rolls-Royce Trent 900 engines here.

In this case, the failure appears to have originated in the high-pressure compressor or turbine sections, creating an uncontained engine failure. Any uncontained failure is an extremely eye-raising event, given its extreme rarity and potential danger, but never more-so than in a brand new design. What makes this one worse yet is the extensive damage it did to the airplane. The worldwide press, usually happy to hype minor incidents out of proportion, has been unusually reserved in reporting this as a mere engine shutdown or loss of a cowling. Photos of the damage to tell an entirely different story:


There are at least two major complete perforations of the wing visible, along with several smaller ones. Fuel vapor is visibly streaming out of the two large holes in the upper picture. Considering that those holes were likely made by turbine blades that have a normal operating temperature of 500-900º C, and that onboard witnesses reported seeing flames around the engine, I think the potential for a catastrophic fire resulting in the loss of the aircraft and 466 souls was very real. I don't think Qantas, Lufthansa, or Singapore Airlines were overreacting by grounding their remaining Trent-900 powered A380 fleets pending initial inspections.

Whether this failure originated in a design flaw or faulty procurement or manufacturing processes, or was simply a one-off fluke, will probably take some time to determine. In the meantime, there will be plenty of very concerned folks at Airbus, Rolls-Royce, and the early A380 operators - to say nothing of A380 passengers. Meanwhile, I don't think anyone at Boeing is popping champaign corks over their competitor's troubles: the forthcoming B787 is powered by the similar Trent 1000 engine, which suffered a very similar uncontained failure during ground testing this last August.