Call it a case of being let down by one's older brother: New delays in the certification of the Comac ARJ21 regional jet could force the development of the C919 mainline commercial aircraft to be prolonged.

The FAA is insisting its shadow certification effort on the ARJ21 be completed before the agency begins work on the C919. But the C919 is already near the point at which a certification agency needs to be brought in; if the project advances much further without the FAA's involvement, the U.S. regulator may decide it can never become involved.

Moreover, Comac has shifted scarce engineers to help sort out the ARJ21's problems at a time when the C919 is already running a few months late. Since FAA endorsement of the C919's Chinese certification is indispensable to the international sales prospects of the 156-seat, six-abreast aircraft, the brewing crisis again raises questions about China's decision to throw its inexperienced industry into development of a second indigenous airliner before finishing its first, the ARJ21. Indeed, the C919 was launched in May 2008, six months before the ARJ21 even flew.

The schedule is unusually important to the C919—not because it is under binding contracts for delivery on time in 2016 (it is not), but because Western competition is mounting. Already Airbus and Boeing, launching the A320NEO (new engine option) and 737 MAX, respectively, have probably obviated the C919s chance to be the most efficient narrowbody in its early years on the market (see p. 26). Beyond that, the replacements for those Western aircraft, whenever they appear, will likely render the C919 obsolete.

Nothing has been announced, but Comac now expects the Civil Aviation Administration of China (CAAC) to certify the ARJ21 as airworthy in September or October 2012, says one industry official. Another executive involved in the program thinks 2013 is more likely, 11 years after the project began.

Comac has yet to officially acknowledge the latest delay to the ARJ21 program. Its last announcement on the matter was that certification would be achieved by year-end. This date already represented a delay from the original, admittedly ambitious, objective of 2006.

Strictly speaking, the FAA's role is to validate the CAAC's process, not the aircraft itself. But officials say the U.S. agency believes it can only be satisfied with the process if it follows it all the way to the end in this test case; only then can the C919 effort begin. A spokesman for the FAA declined to comment.

The CAAC is taking a properly tough line with Comac, says an industry official. There is not the slightest hint of a national regulator going soft on a national-champion manufacturer. In one instance, says another person close to the program, Comac was slow to recognize that a major ARJ21 part had failed a test, even though it very obviously had. Then the company hoped simply to repeat the test. The CAAC insisted on a redesign.

Assuming that regulatory involvement in the C919 design should begin about now—and that the ARJ21 can be certified according to the new, unannounced time table—then the C919 will be pushed back by a year. Some of that delay has been incurred anyway, since the project is now running a bit late. Moreover, Comac has built a year of slack into its schedule. First flight is due in 2014 and first delivery in 2016, allowing two years for certification flying instead of the usual one. A year's delay would eat up all of the reserve time, leaving the program exposed to more of the delays that have accumulated so far.

While an industry official familiar with the C919's design says it will not have the faults of the ARJ21, the latter aircraft's track record does not bode well for rapid certification flight tests. The ARJ21's faults have included problems with the flight control system and an aluminum-alloy wing that broke before reaching its ultimate load. Flight control issues have resurfaced and avionics suppliers Honeywell and Rockwell Collins have been asked to change their equipment, not because it did not meet the specification but because a regulator, perhaps the CAAC, was not satisfied with the specification.

More tests are also needed. A program executive says he expects, or hopes, that if Comac fully satisfies the regulators, then the FAA will relax its attitude.

Crucially, Comac has yet to hand over the ARJ21 to the CAAC so the regulator can conduct its own tests, industry executives say. A regulator would normally need at least 10 months with the aircraft, accumulating 1,000 flight hr., which begin when the manufacturer issues a type inspection authorization. It is not clear when Comac will sign that authorization. And, despite the CAAC's reported punctiliousness, there is the possibility the FAA may take issue with some of the Chinese regulator's processes. If that occurs, there will be even further delays.

One concern that has already arisen is that both the CAAC and Comac have too few qualified test pilots. They are trying to rectify the situation by sending commercial pilots to the U.S. National Test Pilot School in Mojave, Calif., but producing a qualified test pilot takes many months of specialized training.

The delays to the ARJ21 program are also undermining efforts to sign up buyers. The aircraft's export launch customer, Lao Airlines, last month ordered two Airbus A320s rather than wait for the two ARJ21s it had signed for. “Comac hasn't yet received Chinese type certification from the CAAC for the ARJ21. We can't wait,” says Lao's head of planning, Noudeng Chanthaphasouk. The other export customer is Mynama Airways, which signed an order in early June for two ARJ21s. Program supplier Avic said at the time that Comac had four aircraft in the ARJ21 flight program and had accumulated 1,600 hr. of flying time.

Even before the latest certification difficulty, industry executives, watching Comac struggle with the ARJ21, had expected Comac to miss its first-flight and delivery targets.“They still have something to learn about project management,” says one Western engineer. Comac's people are good at working out a solution in a particular area—say, hydraulics—but not nearly so good at balancing costs and benefits in one area against another. This is necessary, because it is the efficiency of the integrated aircraft that counts, not the stand-alone superiority of any particular aspect of it.

Another official says that, despite Comac's ambition of breaking away from the bureaucratic tendencies of Avic, of which it is an offshoot, the commercial aircraft-maker's engineers still show an alarming tendency to push decisions up the chain of command.

Comac announced in December it had completed the preliminary design review, the step before detail design. In fact, many issues—more than usual—remained to be determined, typically the placement of various items of equipment and the volume to be allocated to them. It may be that Comac always expected to have lots of loose ends after the preliminary design review but, regardless of that, they were certainly supposed to be tied up by March or April of this year. A few still remain to be resolved, delaying detail design.

A more recent question is whether to mount the thrust reverser on the pylon as well as the nacelle, taking a further step from the accepted integration of the CFM International Leap-X engine and the nacelle. The materials for the aircraft have not been chosen, but that is not necessarily a problem, because Comac has set a baseline design that one otherwise skeptical industry executive regards as mature. “They are doing well on the structure,” he says. It includes composite inner and outer wing-boxes. Additional advanced material may be worked into it later. The delay in beginning the detail design is not a wholly bad thing, says the same executive. The more time spent on the preliminary design, the less likelihood of foul-ups after the detail design has been completed, he notes.

A spokesman for Comac declined to comment on the certification process of the ARJ21 and schedule of the company's two programs.

Comac announced “orders” for 100 C919s at the Zhuhai air show last November from airlines and other companies associated with the Chinese government or the program, but about half were actually options. Even the orders were not binding, say officials familiar with the contracts, which were signed mainly to save face at China's premier air show.