The aircraft certification process

Aviation International News » January 2007
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December 18, 2006, 5:41 AM

You are sitting in a diner, sipping your fourth cup of coffee, solving aviation’s problems with an old friend, when the idea comes to you in a caffeinated burst of inspiration: a new jet, one that will fill a niche no manufacturer has yet tackled, with safety features, performance, efficiency and comfort that will open new markets and sell like hot cakes around the globe.

You grab a fistful of napkins and begin sketching frantically, trying to get the idea on paper before it loses its luster. Your friend adds some helpful details, the rough outline takes shape, including the number of engines and the basic configuration, and after a few minutes, you start throwing names around. In that diner-inspired creative session, a new airplane manufacturer is born.

Welcome!

You are about to embark on one of the most frustrating, time-consuming, bureaucratically convoluted, mind-bogglingly expensive yet ultimately rewarding business ventures of all.

While nothing can prepare you for how much hair will fall out or turn gray, here is a basic outline about what to expect after the napkin-conceptual phase and advice from those who have been through this process. Aircraft design, certification and production is not for the faint of heart. If you’re not willing to give up a normal life; spend every dime you have and anyone else’s money that you can pry loose; and maintain a positive outlook while the media and other critics rip into your dreams and plans, then tear up that napkin and leave the dangerous journey of aircraft certification and manufacturing to the experts, brave dreamers, call them what you will.

Step 1 | The Idea
After some initial research on the FAA Web site (www.faa.gov), you’ll likely come across some documents pertinent to aircraft certification. You might assume that you should carefully read these documents before doing anything else, but not so, according to David Hempe, the FAA’s manager of the Aircraft Engineering Division, Aircraft Certification Branch. “Those are all tools,” he said, “and just reading them without talking to the FAA probably isn’t going to add much value.”

Instead, Hempe suggests making an appointment for a “pre-familiarization” meeting at the regional FAA office that will handle your certification project. This meeting is where you say to the FAA, “I have a new product; here’s what I’m thinking.” You’ll learn about when and where to submit the application for the type certificate, what will be expected of your organization and of the FAA people you will work with and the kind of personnel you will need to employ to bring the airplane through the certification process.

Hempe has seen all kinds of certification hopefuls during his career, from established manufacturers that have finely honed certification processes to start-up entrepreneurs with no idea of what certification entails and no experience working with FAA certification experts.

“Whether it’s sophisticated or new,” Hempe said, “if it’s a new technology or a new product, the expectation is that you visit with the region that’s going to affect you the most.” Before the pre-familiarization meeting with the FAA, it’s safe to noodle around as much as you want with the design, but keep it simple and don’t go spending money on consultants or the aerodynamicist-of-the-month or any other steps that you think will take you closer to FAA certification. You need an idea of the lay of the land before you start asking questions.

After your meeting is a good time to review the documents on the FAA Web site because they will reinforce exactly what you’re facing, and they will also help you ask the right questions when you begin paying for expert advice.

There are a few ways you can approach the initial design phase. Your napkin was your first inspiration, but it shouldn’t box you into a design corner. The overall goals of the airplane should drive the design. To meet those goals, it’s likely that only a few airframe-engine configurations will be suitable, meaning they can be manufactured productively, operated safely and efficiently and maintained at a reasonable cost.

How the major OEMs conduct this phase can be instructive for new entrants. Most manufacturers were reluctant to discuss these issues, however, probably due to competitive concerns. This whole process–design, certification, production–is the heart of each company’s competitive advantage, its own special secret sauce, and they are not about to reveal the recipe.

Watching companies operate, however, provides some clues and lessons for budding aviation entrepreneurs. Cessna, for example, has an excellent track record with new-airplane programs. The Mustang was designed, certified and has entered production right on the schedule the company laid out at the unveiling of the program four years ago, a remarkable achievement and one that Cessna accomplishes consistently.

Bombardier has much the same record, having certified a number of new designs, although that pace has slowed. Gulfstream’s record is good, too, although it was one of the first to publicize the use of an odd wrinkle in FAA certification, the provisional type certificate, which it obtained presumably to show the financial world that the GV was on the proper certification trajectory during the final stages of its program. The company’s latest project, the midsize G150, was FAA certified in November 2005, at a lower weight than originally planned and with better-than-forecast range and runway performance.

Eclipse Aviation also took the provisional certification step last summer, and Cessna has used provisional certification on one jet program. Raytheon Aircraft made some bold moves in new airplane development with the composite-fuselage Premier I and Hawker 4000, and the 4000 program suffered numerous delays and took twice as long as the company initially announced.

The Hawker 4000 (née Horizon) was provisionally certified in December 2004 and received full FAA type certification almost two years later, last November. Eclipse also took longer than initially expected. Embraer’s record is good, but the Phenom 100 and 300 programs will better illustrate the company’s certification expertise in the clean-sheet business jet arena. Dassault Falcon Jet not only is highly accurate about staying on track but also in its estimates of final weight. New entrant Spectrum Aeronautical projects an ambitious schedule for two new jets; time will tell, as it will for the PiperJet, Cirrus’s planned jet and Diamond’s D-Jet.

The Program Announcement
How much of a new design is complete by the time the company unveils the program at a press conference? Most manufacturers declined to comment, but it’s likely that the design is well beyond the conceptual phase when the big OEMs announce the project to the world. At the time of the announcement, many OEMs have already been through multiple rounds of customer feedback, which helps refine the design and gives early indications of the potential size of the market.

An extreme example of pre-announcement preparation is Honda’s new HondaJet. Michimasa Fujino, president and CEO of Honda Aircraft, has been working on Honda airplane concepts since 1986. It seems reasonable to suppose that he has got through many napkins to arrive at today’s HondaJet.

What is unusual about Honda’s effort is that the announcement of a commercial go-ahead for the HondaJet came not only after the conceptual design phase but also after refinement, wind-tunnel testing and freezing of the design, prototype construction and 240 hours of sophisticated ground and flight testing, not to mention near-simultaneous design, development, testing and installation of a completely new Honda turbofan engine.

Honda Aircraft applied for an FAA type certificate on October 11 and plans to begin deliveries in 2010, which should be achievable given all the work the company has done thus far. The company didn’t begin taking deposits until a week after it applied for FAA certification, just months after it announced that the HondaJet would be a formal program.

By contrast, Eclipse Aviation announced the airplane that launched the recent very light jet frenzy well before the company had constructed a prototype. The actual certification program might take the same time or even less than Honda’s, but an aviation consumer might understandably perceive the Eclipse program to be longer, given the early announcement.

Last-minute Design Changes
Although experienced manufacturers generally wait until the design is close to final before announcing the program, changes often happen during the final design tweaking that inevitably takes place during certification. These sometimes include performance improvements, but often they are necessary to meet an unanticipated regulatory need, a shortfall in performance or something as major as a mid-program engine switch.

The Eclipse 500 grew heavier and sprouted wing tip tanks, for example, when Eclipse Aviation switched from a small Williams International turbofan to the larger Pratt & Whitney Canada PW600. Later, Eclipse had to install bigger tip tanks to achieve range performance goals.

Dassault’s Falcon 7X came out ahead of the performance curve after installation of a forward-fuselage fuel tank, modified winglets and redesigned empennage during the certification program. Launched with a 5,700-nm range, the 7X will be certified at 5,950 nm, although certification is now expected later, in the first or second quarter of this year instead of late last year.

Bombardier has certified 18 aircraft since 1989. The company learned a lot from the rather protracted development and certification process for the Learjet 45. While some of these 18 aircraft are derivative models such as the Learjet 40XR, others are entirely new clean-sheet designs that have demonstrated Bombardier’s robust certification process.

For a new airplane program, Bombardier begins with conceptual development, focusing on the configuration and aerodynamics, and it conducts marketing studies to see how the new airplane might be accepted. “That’s all part of our initial design,” said Dan Burns, chief airworthiness engineer, Bombardier Aerospace. Burns has worked on certification programs for Bombardier for the past 18 years and, along with Transport Canada and EASA certification officials, is a key player in new ways to improve the certification process.

Once the conceptual development is done, the next step for Bombardier is “authorization to offer,” which means that company leadership gives the go-ahead to the program. Only then do Burns and his team prepare to apply to Transport Canada for a type certificate. “Sometimes we take the conceptual design a little further before authorization to offer,” he said. “But once we have authorization to offer, [the program] is essentially public.”

Step 2 | Type Certification Application
Applying for a type certificate is the next step, and the timing is important because this is where the clock starts ticking. Part 23 airplanes generally have three years from the date of application to be certified; Part 25 airplanes have five years. This is a critical stage for any aircraft program because of something called “certification basis.”

When a company applies for a type certificate, the rules that are in force at the time of application are the rules with which the applicant must comply. If, for example, the FAA changed the certification rules after someone applied for certification, requiring that icing tests be done with 100-micron freezing drizzle instead of the current 40-micron droplet size, the applicant would not have to meet that new regulation.

This is where a protracted certification program can run into problems, because if there are delays that push the program beyond the three- or five-year limit, then the applicant has to apply for an extension and might have to comply with rules that took effect after the initial application. This situation recently caught up with Raytheon Aircraft on the Hawker 4000/Horizon program, and Raytheon had to apply for an exemption to post-application fuel system regulations. Raytheon Aircraft will eventually have to redesign the 4000’s fuel system to meet those regulations. Eclipse Aviation also had to apply for an extension of the model 500’s certification program.

The FAA’s Hempe recommends that after the pre-familiarization meeting, an applicant assemble a team that will form the core of the certification effort. The team may include FAA designees like DARs (designated airworthiness representatives) or the company’s own experts under an ODAR system (organized designated airworthiness representative). Spectrum Aeronautical recently received ODAR status, allowing it to hire and train its own team of airworthiness experts who can approve some of the certification work. This should speed up the certification process because Spectrum won’t have to rely on independent representatives who will also be serving other clients on other certification projects.

Hempe cautioned that applicants should be thinking at this point about the end of the tunnel, which is not just the type certificate, although that is one of the three goals of the program. The other two are the production certificate and airworthiness certificates.

The production certificate (PC) is almost as hard to obtain as the type certificate, according to Joe Walker, president and COO of Adam Aircraft, which is nearing certification of its A700 jet and has received type and production certification for the A500 piston twin. The production certificate is basically a quality system that shows the FAA that a manufacturer is capable of reproducing many copies of an aircraft to the same standards.

Efficient Production
Without the production certificate, FAA inspectors would have to inspect every aircraft coming off the assembly line before issuing the airworthiness certificate. With the PC in hand, the manufacturer’s designees can perform those inspections and sign off the airworthiness certificates. “You have to focus on a program that leads to the production and airworthiness certificates,” Hempe said.

Applicants also have to consider how the airplane will be used, how pilots will train and the structure of continuous airworthiness (maintenance) programs. The sooner a manufacturer creates these programs, the better. Bombardier likes to have flight simulators ready before type certification and first delivery and even uses the simulators with their realistic aerodynamic modeling to help with aircraft development, according to chief airworthiness engineer Burns.

As the certification program develops, the company simultaneously updates the simulator. “We use the simulator for engineering support for high-risk maneuvers and for workups,” he said. “It’s not so much practice but trying the maneuvers on the simulator before going in the actual aircraft.”

Step 3 | Certification Program
This is the meat and potatoes of new airplane development, the process of testing and evaluating and proving compliance according to the certification plan. This is also where a manufacturer really begins tapping FAA resources.

The FAA region that is overseeing the certification program assigns a program manager to run the project, and the manager forms a team of FAA experts in disciplines such as powerplants, structures, flight testing, avionics, systems and so on. While the program manager sticks with one certification project, the team members might move from team to team, depending on how much of their time is needed on a particular program. “The system wasn’t set up for us to be at every single place in time for every report that has to be approved,” said Hempe. This is where the certification plan helps because most of the tasks that the FAA needs to directly oversee have already been determined.

The determination of which tasks require FAA involvement is done, said Hempe, “using risk-management approaches from lessons learned in the past.”

Bombardier has been working closely with regulators using a process called “level of involvement” and “work-statement approach,” which Burns helped develop on the Q400 regional turboprop program. This method more clearly defines responsibilities early in the program and provides more detail in the compliance phase, including not only method of compliance but also precisely what kind of testing and analysis will be conducted and whether the regulator or manufacturer designees need to oversee the compliance.

“We agree what [the FAA] needs to see, and that’s what we deliver,” Burns said. “It takes out the ambiguity. We build a work statement, we manage it and if something pops up, the authorities have the right to change something. We try to work with them in partnership.”

The Q400 program also used “gated certification phases,” where type board meetings were held at key intervals to make sure that all required work was completely finished before moving on to the next phase. “If the requirements are not done,” Burns said, “we’re not going to the next phase.” This helps keep everyone involved accountable to the program. The FAA uses a similar process of phase checks.

To speed certification outside Canada, because first deliveries typically take place in the U.S., Bombardier has asked regulators to work together closely. The Global Express program, for example, has three regulatory teams working in parallel on essentially the same certification program. For the Challenger 300, Bombardier’s latest clean-sheet design, there was one regulatory team led by Transport Canada with FAA and EASA members, which helped make the 300 program much more efficient.

Certification by the FAA and EASA now takes place within weeks of Transport Canada’s OK, Burns said, a significant achievement. “We recognize that all three have different processes,” Burns said. “Transport Canada is the state of design, and we want them to take the lead and bring in the FAA and EASA.”

Inevitably, there will be problems during certification, and sometimes they include big issues such as a redesign or change of materials. “We have the ability to generate issue papers,” said the FAA’s Hempe. “It’s a good way to get the issue on the table, then we negotiate an agreement. This is used heavily in certification projects to resolve things that might come up that you didn’t know about in the pre-familiarization meeting.”

In addition to evaluating certification compliance, FAA personnel will also pre-audit production facilities during this stage to help spot any problems that could hold up the program.

Before the OEM flies a prototype of the design, the FAA will need to issue an experimental type certificate. FAA personnel will conduct a safety review and check that the airplane conforms to its design. A plan for test flying will cover all requirements. And before FAA test pilots fly in the airplane it must have flown through its full flight envelope. Flight testing is a challenging part of the certification program and can take a year or more, meeting requirements for compliance with various certification standards, noise testing, reliability testing, human factors analysis and qualitative assessments of the flying qualities to make sure it meets the standards for pilots to receive type ratings.

Proof-of-concept prototypes, which don’t conform to the final design, can be used for flight testing in areas where they do conform, if the test isn’t in an area where non-conformity is an issue.

Step 4 | Production and Delivery
“Anyone who wants to move into the marketplace needs a production certificate,” said Hempe. The best way to make the process of obtaining the production certificate smooth is to plan for production certification in parallel with type certification. That way, you don’t end up at the end of type certification with an airplane that isn’t ready for volume production because the FAA has to perform a detailed inspection on each airplane. Both Sino Swearingen and Eclipse have found themselves in this situation. “Production,” he explained, “is the birth certificate of allowing these aircraft to take the next stage [of development].”

While the certification process is complicated, the actual manufacturing process is another hugely complex operation. There are myriad suppliers to deal with, quality-control issues, problems to fix, development of a quality-control system and then the issues of finishing completed aircraft to customer specifications. FAA designees can help with these, too.

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