Learjet 85 Delivery Timeline Awaiting First Flight Results

Aviation International News » March 2014
Learjet 85
Bombardier Aerospace held a private rollout of its all-composite Learjet 85 on September 7 in Wichita, seen here in a screen shot taken from a YouTube video.
March 1, 2014, 2:55 AM

Bombardier’s Learjet 85 program is moving toward first flight (if it hasn’t already happened after this issue went to press), but the company’s plans to achieve certification and begin customer deliveries this year appear to be unachievable.

In Bombardier’s Fiscal Year 2013 financial results conference call held on February 13, president and CEO Pierre Beaudoin provided some insight into the delays affecting the Learjet 85, which will be the first all-composite business jet certified to FAA Part 25 transport-category regulations and one of the first that has to comply with new regulations for electrical wiring system design. With regard to the challenges of certifying the first Part 25 composite business jet, Beaudoin said, “This is technology that we understand, and we can move forward toward production at this point.”

While the original timeline for the Learjet 85 targeted entry into service last year, that had been revised to first flight last year and deliveries beginning in the middle of this year. The program suffered an early delay when composite design and prototype construction partner Grob Aerospace went insolvent and all design efforts were transferred back to Bombardier. The jet’s design employs two key composite manufacturing techniques: resin-transfer injection (RTI) and curing in an autoclave for the wing structure, which is done at Bombardier’s facility in Belfast, Northern Ireland, and out-of-autoclave oven curing for the hand-laid-up fuselage and empennage, at Bombardier’s plant in Querétaro, Mexico. Final assembly is done in Wichita.

No Timetable for First Flight

On September 7 last year, the first Learjet 85, flight-test vehicle FTV1, was rolled out in Wichita. Bombardier didn’t herald the rollout, and a video that appeared briefly on YouTube before it was apparently removed showed FTV1 (with no N-number painted on it) being rolled out, accompanied by music. While the appearance of the video on YouTube (as opposed to official posting on Bombardier’s website) gave the impression that this was an unauthorized release, other people in the video can be seen using cameras, and the production had a semi-official look to it.

As of mid-February, the first Learjet 85 had not yet flown, and Bombardier said it would not reveal the certification and delivery timeline until after the first flight. Rolland Vincent (who used to work for Bombardier and is now president and CEO of consultancy Rolland Vincent Associates) said he doesn’t expect the Learjet 85 to be certified and delivered until 2016, although he sees a possibility of low-rate production beginning in 2015. “I think it’s 2016 before you see any kind of volume output,” he predicted. Although Vincent (through JetNet iQ and Rolland Vincent Associates) has consultative and special-projects relationships with all the OEMs, what he told AIN represents his own personal and independent views.

No recent Part 25 business jet certification program has progressed from first flight to certification in one year, so even if Learjet 85 FTV1 had flown by the end of last year, certification this year would have been unlikely. The swiftest recent Part 25 program was the Dassault Falcon 7X, which went from first flight (May 5, 2005) to certification (April 27, 2007) in just shy of two years. Gulfstream’s G280 flew on Dec. 11, 2009, and was certified on Sept. 4, 2012. The company’s G650 flew on Nov. 25, 2009, and received certification on Sept. 7, 2012. The Hawker 4000 program suffered repeated delays related to certification issues and took more than five years; this was the first Part 25 jet with an all-composite fuselage, made with the filament-winding method, which uses a fiber-placement machine followed by curing in a giant autoclave (under pressure and at high temperatures). Embraer is projecting certification of its Legacy 500 fly-by-wire jet in this year’s first half, which would put the program about five months shy of two years from first flight and would be a record for recent Part 25 business jet certifications.

According to Beaudoin, speaking at the conference call’s question and answer period, “The delay right now is really more on system integration.” FTV1 “is essentially completed, and it’s the typical thing before we go to first flight, making sure that all the systems are responding the way they should. There have been adjustments here and there that we’ve had to do before we present the aircraft to the FAA. Now we’re very close to presenting the aircraft, and then after that it’s days or a few weeks before we go to first flight.” Beaudoin explained that the certification and entry-into-service schedule will be released after “a period” of flight-testing.

Composites Integration

Vincent believes that the delays in the Learjet 85 program might be attributable to the integration of new technologies, especially the composites manufacturing process. Bombardier declined AIN’s repeated requests for an interview with the company’s composites experts, citing their lack of time because they are so busy with the program. However, in a November 2013 story in CompositesWorld, Bombardier engineering manager Pierre Harter outlined some issues with the program. Harter’s comments came from a speech that he gave at the October SAMPE Tech meeting in Wichita.

According to the CompositesWorld article, Harter explained that the Querétaro facility’s 6,000 feet msl elevation presented the challenge of reduced available vacuum pressure when curing large fuselage parts in the oven. Vacuum is used to suck the air out of composite parts and to hold them tightly to tooling during the cure. The article noted that many problems had to be overcome: “…the OOA [out-of-autoclave] process proved uncommonly sensitive to difficult design features.” But, the article added, “Bombardier eventually developed an OOA manufacturing process that produced voids of less than or near 1 percent.” Following this, “…Bombardier had to perform extensive testing to satisfy the FAA’s special conditions for certification.

“Much of this, [Harter] said, focused on in-flight flammability, post-crash flammability, crashworthiness, durability, toxicity in burn, damage tolerance and thermal expansion at interactions with metals. Results, across the board, were positive.” The article went on to say that Harter believed that the Learjet 85’s composite materials performed better than aluminum in tests of flammability and crashworthiness. That success, he told the Wichita meeting, deserves more attention than it is receiving from aerospace composites professionals. He also said in CompositesWorld that the composite readiness testing had been completed, and that certification testing had started.

AIN contacted engineers who had worked on the Learjet 85 program, and two agreed to be interviewed. One, a composites engineer who asked not to be identified, spent four years on the Learjet 85, including one year at the Querétaro facility. He has not worked on the Learjet 85 for the past two years, however.

The engineer confirmed something that Vincent also told AIN, that the fuselage for FTV1 is not a certification- and production-conforming version. “The structure is different from the aircraft that are going to be produced,” the engineer said.

“There’s still some [work] to be done,” Beaudoin acknowledged during the conference call, “and yes, there will be different configurations, which is typical from one flight-test vehicle to another.”

The delays in the Learjet 85 program started with the original Grob plan, which was to use a process in which composite fiber is laid out, then sprayed with resin and cured in an oven. The low-pressure, out-of-autoclave, oven-cured technique that Bombardier chose for the Learjet 85 uses carbon-fiber fabric that is pre-impregnated with resin but still laid out by hand. Several early fuselages were scrapped, the engineer said. “The problem is porosities. You have air entrapped in bubbles and it can crack. You need to have process control that gives you good parts.” The factory learned more and more with each fuselage, he added.

Challenges of New Requirements

Harold Cooper, an FAA designated engineering representative who specializes in avionics and electrical systems, suggested another factor that could have added to delays in the Learjet 85 program. Cooper was a contractor on the Learjet 85 until last December and currently is not involved in the program.

“This didn’t have anything to do with composites,” he said. He believes that the problem is a new Part 25 certification requirement called Electrical Wiring Interconnect System (EWIS). The EWIS regulations took effect in 2007, so new jet certification programs embarked on since then have to comply with EWIS, which applies a systems approach to wiring and thus requires many more engineering reports during the certification process, not to mention overcoming the FAA’s own learning curve in applying the new rules. “That’s a whole new certification program that’s never been done before on a [transport-category] aircraft,” he said.

AIN confirmed that neither Gulfstream’s G280 nor G650 was required to comply with the EWIS regulations, although Gulfstream engineers did apply EWIS standards to the fly-by-wire G650, according to a company spokesman. These two airplanes are the most recent Part 25 business jet certification programs. AIN was unable to establish by the time this issue went to press whether EWIS is required on Embraer’s Legacy 450/500.

Rockwell Collins, which is supplying the Learjet 85’s Pro Line Fusion flight deck, told AIN it “is fully prepared to support Bombardier with first flight of the Learjet 85. The new EWIS regulations haven’t resulted in any major challenges for us on the aircraft. We have provided support to Learjet as necessary to ensure the avionics wiring and mating connectors are fully compliant with requirements.”

“Relative to the FAA regulations on EWIS,” said Learjet 85 supplier Astronics AES, which is providing its CorePower electrical power distribution system, “the CorePower components facilitate our customers in meeting those requirements through the system’s solid-state design and the improved wire protection provided with our configurable fast-trip characteristics.” The CorePower system includes the company’s electronic circuit breaker units, which not only protect circuits but also “provide switching and control capability, reducing or eliminating the need for stand-alone system controllers and switches.”

Asked whether problems with composites were causing delays, Beaudoin said, “I feel that we’ve made significant progress on the composites, and that we understand exactly what needs to be done for production, and we feel that this is technology that we understand and we can move forward toward production at this point.” Asked whether the electrical system design is part of the delay, he added, “Not specifically, no.”

Whatever the reasons for the delays in the Learjet 85 program, Bombardier is facing a challenging confluence of tasks: flight-testing the CSeries airliner; getting the Learjet 85 fit to fly and certifiable; and ramping up the Global 7000/8000 program.

“I think it’s the integration of all these technologies,” said Vincent. “I’m a believer in the Learjet 85 and I think they have a nice concept and design.” However, Vincent, who is also a Bombardier shareholder, would prefer that Bombardier leadership be more forthcoming about the Learjet 85 program’s issues. “I think we’re looking at delays,” he said, “and I think they’re significant.”

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