777-200LR Flight Test Journal: Archives

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31 October 2005

Heart of the plane

Anngelique Bowen, AIMS Platform Engineer

Rochelle Mai, Displays Lead Engineer

Wayne Fortner, Technical Focal, Flight Data Acquisition & Recording Systems, Flight Deck Printers

Edward Nolte, Jr., Avionics-Flight Management/Guidance Lead Engineer

For us in the Aircraft Information Management System (AIMS) group, Flight Test is the fun part of our jobs. It's when we see the new functions actually working on the airplane. It's always rewarding to see what you've designed on paper actually working in the air. Then, after you fly it, the best is when the pilots and customers say the addition is a good thing. That is what we strive to do.

AIMS is the heart of the plane. It provides flight and maintenance crews pertinent information concerning the overall condition of the airplane and interfaces with more than 70 different systems. This critical information converges in the flight deck. There are eight main AIMS functions: Displays, flight management, central maintenance, thrust management, flight deck communications, aircraft condition monitoring, data conversion gateway and flight data recorder.

Our group, about 25 people, works in Everett, Wash. We don't travel to exotic places for testing. Our test flights takeoff from Renton, Wash., and usually last 2 to 3 hours. The Flight Test for the 777-200LR Worldliner has had its hurdles. Our time between verification tests and the certification tests has been compressed. Plus, we are testing the 777-300ER Enhanced simultaneously.

Our biggest challenge is communicating between engineering and Flight Test so everyone understands the new features. Some of the new functions specific to the 777-200LR are an upgrade to the Aero Engine Database for the new airframe and larger thrust engines, an airspeed correction change required for the location of the static probes and auxiliary fuel tanks.

We work in cycles of 18 to 24 months, called Blockpoint updates. We are working on Blockpoint 05 right now. Flight Test is the final stage of that cycle. In the beginning, we gather input on new features from member groups, pilots, customers, and the sales team. We have strategies across Boeing and synthesize what's most important. We ask the supplier the cost. If management approves, we design and specify the new systems. We send specifications to our partner supplier, Honeywell, which builds it. The system comes back, and we do the higher level validation testing. If there are problems, we work with our supplier to fix the bugs.

Before a flight test, we develop a tip sheet. It's the procedure of conditions we want to check. We lab test the changes before we fly. There is a tip sheet dry-run on the ground. We always have an AIMS engineer on board to video tape the displays.

After the flight, we get a flight test report, typically the same day. We might also receive a "squawk" report, the pilots' comments when something does not work as expected. When a problem occurs, we help determine the root cause. Many times our displays are the messengers of trouble in other parts of the plane. First we have to understand if it is a tip problem: the way it was written, or a logic problem, or maybe it wasn't performed correctly. We request flight data and match it to the video, if necessary. Our displays are always guilty until proven innocent.

We also have to be nimble. For example, the 777-200LR has space for auxiliary fuel tanks. We planned on testing instruments to monitor the auxiliary tanks, but they weren't installed, so we could not test it. The customer has since decided to add the tanks, so it will be tested at a later time before delivery.

We are finishing final certification for Blockpoint 05 and then we'll start some small changes, referred to as Block 05A enhancements. We always look for ways to make the airplane more useable, more valuable to customers, more accurate and more efficient.

Flight Test is the way we prove that we accomplished our goals.

25 October 2005

At your service

Stuart Kramlich, flight test program manager, General Electric

Boeing uses a lot of engines manufactured by General Electric (GE) in its products. This is no surprise considering the number of flight test programs, research projects and commercial jetliners the company manufactures and operates. Anytime a question or issue comes up about a GE engine, it comes to the onsite engine support team in Seattle.

There are approximately 24 GE support staff onsite at Boeing. We're the point of reference for anything to do with the engines; we're the go-to people for the engine vendor. It's a lot more efficient than making Boeing work through a dozen separate contacts back at our manufacturing facility. Questions and issues can range from the engine's hardware configuration to operational issues, such as why the engine is behaving in a certain way. We take care of everything.

I manage the flight test program for the 777-200LR and the -300ER. The team's focus is generally divided among the different airplane models, but our support stretches beyond production and flight test to special projects, like the second Quiet Technology Demonstrator (QTD-2) program in Glasgow, Mont., in August. A good example of other areas we support is the flight test program. Supporting flight test involves a lot of planning, so we monitor schedules and get the aircraft ready for remote flights and testing. We'll put together lists of spare parts we think the engine might need, and they'll be waiting for us at the airplane. We work closely with Boeing to make sure any items or personnel we might need are there to support the scheduled testing.

Sometimes the engine might need special adjusting to complete a test. For example, some adjustments will disable certain engine systems to help us get a baseline performance understanding of how the engine works.

Even with our best planning, test conditions can change instantly, often because of the weather. We were trying to get the 777-300ER to Yuma, Ariz., in September to test what's called a thrust bump, which gives the pilot an option to get out of a hot and heavy airfield. If it's at high altitude and the airplane is full, the pilot has the option to use the bump. We needed 107 degrees to do the test but couldn't schedule the remote in September. Now those temperatures in Yuma are gone. We'll probably have to fly overseas to find the right conditions.

In supporting flight test, it's good to remember to expect the unexpected. Sometimes, issues come up that are outside of our experience. It gives us the chance to work things out in real time on the spot. This is a very dynamic job. If you live by a schedule and don't like change, this is not a job for you. You need to be able to respond and adapt quickly and be able to make decisions with the data you have on hand. That's what I really love about it. I come into work never knowing what new opportunity will develop in supporting our products.

21 October 2005

Protecting your tail

Steve Louthain, lead engineer and equipment manager for the Primary Flight Computer

For the Flight Controls teams, FAA certification testing is a long process that began last winter in the earliest stages of the 777-200LR flight test program.

New software is being developed and tested for the Primary Flight Computer (PFC). For the 777-200LR program, the Primary Flight Computer group's focus is to test new software in the primary flight control computer. In addition, we collect data during flight test which cannot be accurately predicted in the simulator in order to modify and tune the functions and control laws.

Changes to the airplane itself are primarily what drive the development of new software. We had relatively few significant changes for the 777-200LR PFC relative to its predecessors. For the 777-300ER we introduced several new features to the Flight Controls system, and new hardware was introduced to bring the hardware design up to the state-of-the-art. For the -200LR we are activating those features and customizing them for the new airframe.

Tail strike protection is a function designed to reduce the probability of the tail of the airplane striking the runway on takeoff and landing. The tail strike protection system was first introduced on the 777-300ER and has now been incorporated on the 777-200LR.

The challenge in the tail strike protection application is the calculation of the height of the tail above the runway during takeoff and landing. This calculation is fairly complex because there is no sensor on a production airplane that measures the height of the tail. Tail strike protection provides a command to the elevator in order to prevent a tail strike only if a tail strike is imminent. If the airplane is in danger of a tail strike then the proper amount of elevator command must be applied, and it must be transparent to the flight crew. Therefore the calculation of the tail height must be very accurate and timing is important.

In flight test, there are specific takeoff and landing conditions that evaluate the PFC's calculation of the tail height. The flight test airplanes have a laser sensor installed at the tail of the airplane that measure the actual height of the tail above the runway to within a couple of inches. We analyze and compare the calculation of tail height versus the actual measurement. This allows us to optimize the PFC's calculation with a software update during the flight test program. We then perform additional tests to confirm the optimized calculation is performing well.

On a fly-by-wire airplane like the 777, the flight controls function interfaces with multiple airplane systems. We also work closely with the Aerodynamics and Dynamic Loads groups. Many of our system requirements are driven by those groups. This makes for a pretty dynamic work environment.

One of the primary flight controls functions driven by requirements from the Aerodynamics/Stability and Control group is Landing Attitude Modification (LAM). The PFC drives multiple wing surfaces to modify the pitch attitude of the airplane on high speed approaches. The LAM design went through several iterations during flight test, and was one of our biggest challenges for the program. Changes and problems with the LAM design were the biggest source of long days and late nights.

One of the other big challenges during the program was troubleshooting problems squawked on the airplane and troubleshooting problems identified while lab testing software updates. The pressure was on to find solutions quickly. We analyzed flight test data, analyzed requirements and software implementation, and ran lab tests in our standalone lab and Flight Controls Integration Bench.

The -200LR flight test program has been a great and exciting experience. One of the most rewarding aspects of the program has been working with the talented engineering and flight test team.

19 October 2005

Testing the flutter

Frank Roney, Loads and Dynamics manager, Structures

Keith Wing, lead flight test engineer, Structures

Safety, obviously, is the top consideration in flight testing the 777- 200LR or any other Boeing airplane. The Structures group plays a key role in making sure all flight tests that could affect the airplane platform are conducted within guidelines that guarantee its structural integrity and airworthiness. We don't want to inadvertently damage an airplane in flight test.

The Loads and Dynamics organization determines the airplane's structural requirements based on the configuration definition and basic performance characteristics. The airplane design incorporates these requirements and is tested in two ways: to validate that the requirements have been met, and to ensure that FAA certification criteria have been addressed. One of the first tests we perform is "flight flutter," to make sure the airplane is stable in flight at speeds greater than 270 knots, or Mach 0.70. Flutter is a phenomenon that is related to vibration modes. When an airframe is exposed to high aerodynamic forces, these vibrations could become unstable and grow to a point where the structure may fail. Our goal is to make sure the aerodynamics, weight and stiffness come together to make an aero-elastically stable airplane.

As a result, flight flutter testing is considered "high risk." Consequently, it is the flight test engineer's responsibility to produce a safe test plan. One tool we use to mitigate the risk during flight flutter testing is telemetry. Using telemetry allows us to have a minimum crew (pilot and co-pilot) onboard the aircraft while the balance of the test crew supports the flight from the Telemetry Room where they analyze data and keep the airplane safe.

One of our main safety-related jobs in the flight test program is to prepare a series of structural Temporary Operating Limitations (TOLs). To get an airplane certified, we test all of its performance requirements, including stalls, engine-outs, 2.5 G maneuvers, and so forth. The TOLs set test-limit values so that if the tests are conducted within the prescribed constraints, we can be confident that the maneuvers will be completed safely. If the tests exceed the guidelines, we have to conduct data analysis and/or inspections to make certain that the airplane structure will not be, or has not been compromised.

The initial TOL values are less than or equal to limit load. Limit load is established by a mixture of FAA certification criteria and Boeing design requirements. Coupled with a safety factor, this establishes the strength at which we design and build the airplane. And as much as we aim to get our structure-related testing done inside the TOL values, we know that many tests just can't be done that way. For example, speed and over-weight landing tests need to push the envelope. Or we may be required to go to the edge of 2.5 Gs and stall the airplane. We design the airplanes to take the stress and loads, but only under closely controlled conditions. This is where the Flight Test Structures group gets involved. We monitor the day-to-day testing performed by other flight test disciplines, such as Stability and Control, and make sure what they're doing is safe.

Overall, we believe a lot of the Structures group's talents come to the forefront when we're able to develop a test that works for everybody. We feel the pilots are very comfortable with stability and control and how the airplane feels and how it's controllable. But they depend on us to make sure it's structurally capable. We all use our processes to make sure the airplane is safe. That's one thing I think we can hang our hat on. We have the best processes in place to make sure safety happens, from start to finish.

12 October 2005

The brains of the engine

Shahrokh Ghayem, Propulsion Controls Lead Engineer

Mathew Metcalfe, Propulsion Controls Engineer

Peter Douglass, Propulsion Controls Engineer

Grazyna Ostrom, Propulsion Controls ATF

Kevin Brown, Propulsion Controls Engineer

Kyle Peterson, Propulsion Controls Engineer

As the Flight Test program for the 777-200LR Worldliner heads into its final few weeks, final certification work is underway on the Electronic Engine Control (EEC). That is our piece of this glorious machine.

The EEC is basically the brains of the engine. In reality, it is also an avionics box that resides on the engine. Its purpose is to control the engine functions, interface with the aircraft and allow the pilots on the flight deck to modulate thrust and control the function of the engines. It also provides indication to the pilots of the health of the engines.

For the 777-300ER and -200LR, General Electric developed a new generation of EEC, known as Full Authority Digital Electronic Control-3 (or FADEC3). It contains all new hardware with more memory, a new processor, and more thorough capacity in a smaller space.

In terms of flight testing, a lot of what we do is ride-along testing. Our box is just on there controlling the engines, and we monitor it. We get data off of everyone else's flight test, especially if anything unusual or interesting happens. There have been no problems related to propulsion or our function. We get daily reports from the people who are flying along and every day the reports come back and say, "No problems or issues." Don't get us wrong ... we enjoy the fact that everything is going so well. It's not bad, just a little monotonous.

In addition to supporting everyone else's testing, we have our own dedicated testing, which we are doing to look specifically at EEC functions - like thrust settings for various takeoffs and different runway altitudes and temperatures. We have our own dedicated certification tests to evaluate those, and we also look at some in-flight conditions. For instance, we'll shut down an engine in flight and restart it just to demonstrate that it can be done. We also do some refused takeoffs - heading down the runway and then putting on the brakes, pulling the throttle back and stopping.

The EEC is actually part of the engine system. As such, it gets certified by the engine manufacturer. We are not really certifying how the EEC controls the engine. We are certifying that it meets our airplane requirements in terms of performance and in terms of integration with the airplane.

Our work on this program started way back before the first 777-200LR was built. Nearly three years ago we went through and verified a lot of the functionality in the Propulsion Integration Laboratory (PIL). The PIL has the full avionics system for the airplane. It has all the displays, the avionics bench and a simulated flight deck. The engine, the airplane and the atmosphere are all simulated. We have a large rack of electronic equipment that translates data from simulated into real signals, which we then feed into the EEC. So, the whole purpose of the PIL is to trick the EEC into thinking it is really running an engine in flight. After you do that, you can introduce faults and test just about anything you want.

We spent several months in the PIL verifying a lot of the functionality, especially the Engine Indicating and Crew Alerting System (EICAS), which generates the messages that the pilots see if there was some condition they needed to be alerted to - things like cautions, warnings and advisories. In addition, we perform fault insertion testing to check the engine related maintenance messages to which helps engine maintainability and reliability.

By doing all this work in the PIL, we save a lot of money because flight testing is very expensive. It also allows us the opportunity to solve problems ahead of time and ensure that the flight test program is able to run as efficiently as possible and stay on schedule.

09 October 2005

The human side of Flight Test

Les Tomminger, Flight Test Manufacturing Maintenance crew chief

I've been involved with Flight Test for 19 years, and I spent the better part of a month this past summer at Edwards Air Force Base in Cal., supporting WD001, the first 777-200LR Worldliner, as it went through part of its Flight Test program.

When we take off for places like this to do testing, it is called a "remote," and I've been asked to tell you a little about the "human" side of a remote operation. Of course, I'll also have to refer to some of the work we do because that's what these remotes are all about. It's not possible to separate the human side from the work side - they are wound tightly together.

Remotes are very efficient. This probably seems strange because the people involved leave behind their regular workspace and go someplace where they don't have easy access to equipment and other resources. When we go on a remote, we have to take everything we need with us - and if we forget anything, we have to wait until it arrives. Unlike Everett or Boeing Field, we can't just pull someone off the next plane if we need more people or someone gets sick. We have to make do with what we have.

So how can that be more efficient? Well, for starters, everyone on the remote is very focused on the job at hand. We leave our families, friends and other distractions behind while we are there. We've all made the commitment to stay until the job is done and that certainly makes it easier to concentrate.

Secondly, and probably just as important, is the fact that we are removed from many of the meetings and other cumbersome aspects of our jobs in the Puget Sound area. And finally, the teams we bring with us are hand-picked and are made up of high-performing people who know how to get along and work in a team environment.

Doing a remote from someplace like Edwards, which really is "remote," also makes the job easier. There is not a lot to do around there and, therefore, there are few distractions. And the traffic is great - because there isn't any. I've been on remotes all over the world - Hawaii, Singapore, Australia, Japan, Taiwan - and, of course, there are a lot of things to do and see in places like those.

When we take off on one of these remotes, we know we won't be home for a while. Some people think that when we clock out on Friday afternoon we all get to climb into a plane and fly home for the weekend, but that isn't the case. First of all, no one clocks out on Friday. We work practically every day we are there. Even when the plane isn't flying, there is plenty for everyone to do.

If a remote lasts more than 30 days, the company makes arrangements for your spouse to join you for a few days. The longest remote I have been on was two years in Hawaii. I was able to take my entire family with me. Parts of it were really nice, but we were happy when it was over.

Now, I don't want to give the wrong impression about Edwards. When we are not working, we are having fun. I don't think you'll find too many people watching "Oprah" in their hotel rooms in the evening. There is a lot of camaraderie during these remotes - there has to be. It's a team, and most everyone likes to work hard and play hard. Of course, the playing has to end pretty early because our work day begins at 3 a.m. - even earlier for some.

So there's what I can tell you about the human side of a remote. It is all about getting the job done and getting along with your co-workers. I sometimes wonder why we have to go someplace else to do that so efficiently.