Keeping standards: Twin engine certification


There are two areas of enormous development with civil airliners: commercial change and technological change. It can be argued that the biggest game changer was the breakthrough in certifying twin-engined larger airliners

It is one of those interesting games to ask what the biggest breakthroughs in commercial aviation in the last two decades have been. There are of course a number of contenders, ranging from the engineering-led introduction of new aircraft types, to purely commercial innovations such as charging for checked luggage.

Boeing’s B777 (and then the B787), as well as the Airbus A380, are examples of game-changing aircraft. These aircraft are technological breakthroughs, as well as feats of engineering. They were borne on shoulders of huge technological investment and follow-through, as well as a lot of hard work. It was the engineering half of the aviation industry that did that work.

However, that is not to down play the commercial half’s contribution. A second way to answer the question is to look at what the airlines have done with these new pieces of technology. The B777 is directly responsible for the rise of the Gulf-based carriers and the changes they have brought to the international aviation market. It changed airline economics forever.

Before the twin-engined B777 there was no aircraft big enough to fly long routes but small enough to do it efficiently and economically with smaller payloads. Smaller cities, away from major airport hubs, suddenly found themselves able to be served on a regular basis by long-haul aircraft. Long-haul aircraft meant that passengers were spared the need for short flights to major hub airports before being transferred to a large aircraft, inevitably a B747, for a long-haul trip.

But it is not just the airframe that is responsible for this revolution in air transport. In fact the real breakthrough was granting approval to carriers to operate twin-engined aircraft for up to 180 minutes on only one engine. Without ETOPS180, the B777 would have been a very large small jet.

ETOPS granted

The ETOPS certification (Extended-range Twin-engine Operational Performance Standards) allowed these twin-engined aircraft to operate where they could be most effective. ETOPS certification is a measure of how many minutes the aircraft can continue on one engine. As approval moved from 120 to 180 and now 240 minutes, the missions that the aircraft could safely fly grew. ETOPS180 made it possible to fly non-stop in a fuel efficient and economically viable aircraft without the need to hub passengers through larger airports. It opened up the range of possible city pairs.

Now, as extended range aircraft are produced and operated around the world, it is easy to underestimate both the significance of the first ETOPS certification and just how hard it was to bring it about. But we should stop for a moment and do just that.

The certification section of the FAA is not easily impressed and even less easily convinced. It is open to being convinced, but it is just that the convincing cannot be taken for granted. You would not want it any other way.

We should also be very thankful that the engineers at Boeing, the engine manufacturers and various airlines were prepared to do the work necessary to be convincing. Had they not, the industry would not look as it does today.

Mountains of paper were needed to convince the FAA staff of the risks, or more accurately the (lack of) magnitude of the risk that this procedure involved. In a nutshell, the risk is that not one, but both engines fail on the same flight, consecutively rather than simultaneously.

A catastrophic failure of both engines was not the issue. As terrible as it is to contemplate, that leads to other outcomes. The risk that needed to be assessed, quantified and reviewed was that the second engine fails even as the aircraft flies to an alternate airport after the failure of the first engine.

You might well say, so what? Testing takes time and precision. That is the normal way of aviation. Yes, it is. And it is equally normal that the process, the painstaking and laborious process, took more than two years. Two years, it should be stressed, that happened after the aircraft had entered commercial operations. Once the approvals were given, airlines need to train their pilots, amend their manuals and review their procedures.

The two sides

This neatly brings us back to the great dividing line between technical and commercial departments. The technicians knew what was going on and why. The commercial people wanted the aircraft to do what they bought it for. For those that wanted a long-haul, game-changing aircraft, it was an agonizing wait. For those that just wanted a medium-haul twin-engined aircraft, not only was this work unnecessary, but it let the genie out of the bottle and changed aviation for ever.

We risk a similar situation today in the move toward new air traffic management systems. A huge amount of work and effort has gone into designing new systems, but deploying them will require safety approval. That process will take time. Airlines will demand that all this fancy new kit be introduced and deployed as soon as possible, but the safety procedure, the testing and certifying will still need to be done. Painstakingly, just the way we need it to be done.

At this stage, no new procedures have been written, no safety cases approved. There is an irony here, of course, in that we are now demanding these safety standards of equipment and procedures that will replace equipment and procedures that are very unlikely to have passed today’s standards, had they applied, when the equipment was first installed. Nevertheless they do apply, and for good reason.

The second irony is that having proved the safety of these new systems, filling several rooms with paper, and writing a number of complex documents and procedures, the engineers that obtain this safety certification, and the regulators that issue that certification, will then drive home at speeds approaching that of aircraft about to take off, facing objects moving at similar speeds along the same piece of tarmac, separated only by a line of paint 10cm wide. Where is the safety assessment of that?

Andrew Charlton is the managing director of Aviation Advocacy, an independent air transport-focused strategic consulting and government affairs consultancy based in Switzerland. It was established in 2006. Charlton has wide-ranging experience in the legal, commercial and aero-political aspects of all parts of the aviation industry. He has been involved in some of the most major developments in the industry. Previously he was the chief legal officer of Qantas Airways before being responsible for government affairs for IATA and then SITA

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