777-200LR Flight Test Journal: Archives

12 July 2005

36,000 measurements at 30,000 feet

John Corrigan

Lead Test Operations Engineer, WD001

I have the overall responsibility for day-to-day test planning on WD001, the first 777-200LR. And there are a lot of decisions my team and I have to make. What tests are we going to conduct each day? Where are we going to take the airplane to do the testing? Where are we going to position people?

With the runway construction we have going on now, we can't always return back to Boeing Field in Seattle because of the restricted runway length and aircraft weight. Sometimes I have to ask people to position themselves at Paine Field in Everett.

I put out the test schedules that people monitor. There is a three-week schedule, which is a look ahead to where we think we're going day-to-day with flight tests. It's a very fluid and dynamic schedule. A lot of things interplay that could cause it to change. Typically, it's things like weather. We conduct test flights that require calm winds or lots of wind, or multiple things, like turbulence or heavy rain. We may need special runways. It all drives how you do the day-to-day test scheduling.

Every day is different in the life of a flight test engineer. It's not an 8-to-5 type of job. On any day you're not really sure when you're going to get to go home, because you might be 30,000 feet over Montana at 4 o'clock and you're still two hours from home.

The most challenging time recently was the trip to Edwards Air Force Base in California. One of the reasons we go there is for take-off performance testing. We need very calm, quiet air in the morning hours. Typically when the sun comes up is the most calm. So we have to leave the hotel at around 3:30 in the morning to be at the airplane by 4:40 and start the engine by 5:15 to be testing the first take-off by 5:30.

We always define our take-off speeds at Edwards, so we have to find the speed the airlines will use for various conditions. We do it first for Boeing and decide what speeds we want to recommend. Then we bring down the FAA and repeat some of the testing to get the airplane certified. That is what goes into the aircraft flight and performance manuals.

We have an array of instrumentation that we use for data collection and analysis. We have roughly 36,000 measurements at any given second being recorded from all points on the airplane, both analog and digital. We tap into those data streams and we can pick the information off and record it. We know exactly what the airplane is doing during the flight. We're always recording, so if something unplanned happens, the data is there for engineering to review.

A flight can last anywhere from one to eight hours. And when it's over, we come back and talk about it, the lessons learned, and any anomalies we may have found. We ask, is the data acceptable? Do we need to repeat anything? Are we ready to go on to the next step?

If you can't handle change, Flight Test is not the place for you to be. But it's very fulfilling to get through a test program knowing that you've met all these hurdles and challenges.

Somehow you get it done and you end up with an airplane that is certified.