I know much of the public has absolutely no idea what an airplane goes through before any airline flies passengers in it, I didn't either until I worked in a Flight Test organization and supported one during the certification process.
Back in 1994, I was assigned to the first 777, known as WA001, the “Working Together" workhorse of the 777 certification process. As part of the Instrumentation Group, we supported the airplane 24 hours a day, and usually seven days a week. The actual certification process took almost a year to complete from the time we started supporting the airplane during the buildup in the factory.
In all, I think Instrumentation was represented by about 13 engineers and techs. We rotated our schedules so that first shift flew, second shift did all the troubleshooting of instrumentation from that day's flight, and they began the preflight for the next day, and third shift did the majority of the preflight for that day's test. We all did our part and we all rotated our shifts. “Working Together" wasn't a meaningless slogan painted on the side of the airplane, it was for real and crossed all boundaries of the company. There is no way we could have accomplished as much as we did if everyone did not work together. Sure, there was the occasional personality squabble, but everyone seemed to put these issues aside quickly and move on with their assignments.
Without getting into too many details, I wanted to briefly list some of the things we did that led to the 777 being the finest airplane of its kind in the air.
Refused Take-Offs - or RTO's. This testing is to certify the tires and brakes used on the airplane, and since we had multiple tire and brake options for our customers, meaning multiple manufacturers, we had to perform several of these tests. The objective is to demonstrate that if an airplane is rolling down the runway with 100% worn tires and brakes, and the pilot determines that he cannot take-off, the airplane will be able to safely stop in a specified distance without any catastrophic failure of the brake/tire system. These are fun tests (for the non-pilots), but they are very demanding of everyone involved. There is a build-up to the actual test that involves incrementally increasing the airplane speed to the certification speed so that if there is a problem of any kind, it is found before the speeds are too high. This test was done at Edwards Air Force Base so that if the airplane was unable to stop, it could roll out onto the dry lake bed. Since I was there for these tests, I can say that everything went well and the airplane surprised us all by stopping well short of the expected distance.
Stalls - This is the most fun to me. Imagine riding a roller coaster without tracks and you can envision what it is like to fly in a 777 when it stalls. There are many different kinds of stalls involving different speed, flap settings, thrust settings, stab settings, etc. , in many different combinations. Some are a lot wilder ride than others, but my being here after about 450 777 stalls is proof that the airplane does recover, and I might add, quite nicely.
Intentional Tail Strikes - On occasion, an airline pilot will begin his take-off a little too early and the tail of the airplane will strike the runway. On the first 777, we went to extreme lengths to define what the minimum speed required of the airplane is for any flap setting on take-off. This involved attaching a very heavy (structurally speaking) skid to the tail of the airplane. The tail skid had heavy laminated oak wear pads so that when the tail did strike, the oak would grind away as the airplane continued its take-off. We also had a ground proximity laser to measure the distance from the tail to the runway and a “tail wand" that actually struck and rotated, giving the pilot very accurate information about when the tail was actually going to strike the runway. The testing we did required changing the oak planks several times, and the wear surface was about 18" x 30" with about 10" to wear before requiring a change. This was usually good for a single tail strike.
Wind-Up Turns - These are maneuvers done where the airplane is put in an increasingly smaller turn requiring more and more pitch to be applied while the airplane is banked. The feeling is much like being on a merry-go-round that is turning faster and faster as you experience an increasing g load.
Roller Coasters - This is generally a straight ahead maneuver requiring that the airplane be pitched up and down so that the path would be like driving down a road going over many hills - very fast. Quite often the objective it to pitch up to near stall and then pitch down to zero g's.
Negative g Maneuvers - As the name implies, the objective is to get the airplane and contents between 0 and -1 g's. These are a favorite of the participants in the back (except those with weak stomachs) and it always seems everyone has their harness as loose as it will go so they can almost stand and watch everything that is not secured fly around the cabin. Fortunately, these tests are only done after the airplane has been thoroughly inspected for loose items. You might not give it much thought in your daily life, but something as seemingly harmless as a flashlight can be deadly to people when it is flying around in the cabin of an airplane experiencing negative g's. Before we ever did these tests, the pilots would always have us thoroughly patrol the airplane - even after it had been done on the ground.
There are literally dozens of other exciting tests that are done on an airplane during the certification, but there isn't enough room to address them all in this article. I have been flight testing airplanes since 1992, including the 737-300 (prototype blended winglet testing), the 747-200 (prototype blended winglet testing), the Raytheon Hawker (prototype blended winglet testing), the Canadair CRJ-700, the Bombardier Dash 8 400, the 777 basic certification and ETOPS certification, and the F-22, and it has taken me to Glasgow, Montana, Roswell, New Mexico, Victorville, California, Riverside, California, Marietta, Georgia, Wichita, Kansas, Toronto, Canada, Montreal, Canada, Belfast, Northern Ireland, Edwards Air Force Base, California, and a host of other short stops. It has been fun and exciting from day one.
While testing the 777 at Edwards AFB in 1995, I met up with a friend from high school that I had not seen since 1973 and brought him out to watch us perform a pre-flight on third shift. About all he could say was, “Man, you are living the dream, " and he was right.
Michael E. Mould is still working in the Flight Test Validation Instrumentation Group of that big airplane company in Seattle, and is still living the dream testing the 787 flight control software and preparing for the 787 airplane.
He is the author of the book, “Online Bookselling: A Practical Guide with Detailed Explanations and Insightful Tips, " [CD-ROM ISBN 1599714876, Paperback ISBN 1427600708] and the developer of “Bookkeeping for Booksellers, " [CD ISBN 1427600694] a 19 sheet tabbed and linked Excel Workbook to assist online booksellers track their business performance and prepare their in-state retail sales tax obligations/reports and their Schedule C.