777-200LR Flight Test Journal: Archives
08 July 2005
To the ends of the earth
Eric Garday
Lead ground operations engineer, WD001
On WD001, we typically perform Stability & Control and Aero Performance testing. We run the airplane through its full paces and go anywhere in the world to get the conditions we need to meet the engineering flight test requirements. To put it bluntly, we test the airplane in the worst case scenarios, sometimes outside the envelope, to prove to ourselves first and subsequently to the FAA that the airplane meets or exceeds its design capabilities.
As ground operations engineers, our primary purpose is airplane configuration control.
This means we evaluate the test requirements and determine which components, hardware, and software are required for the conditions on any day's scheduled testing. This includes the airframe, engines and Line Replaceable Units (LRUs), which are typically the computers that receive inputs from the flight deck to control the airplane's systems. Basically, every piece of equipment that is new or uncertified on the airplane will be tested.
A rare glimpse of both Flight Test airplanes together at Boeing Field in Seattle.
We continuously move in and out of different configurations. For example, on a recent trip to Edwards Air Force Base, the Lead Test Operations Engineer determined a set of contingency tests to make sure we acquired test data on any given day. Most of the Edwards testing needed calm air on the spacious runway. If the winds were beyond the acceptable limit, we would change configuration, sometimes two or three times a day, to acquire the data for a specified set of test conditions.
The testing we conducted at Edwards was the Minimum Control Speed (Vmcg) and it was for FAA certification. Certification testing requires the airplane configuration to be conformed by an FAA representative and the tests are evaluated by an FAA pilot and engineer.
Part of the ground operations engineer's function is to fly onboard the test flights as the weights engineer and safety officer. As weights engineer, or "weights," as we are called during the flight, we track fuel burn from multiple fuel tanks, high lift systems, and landing gear position and ballast. This is critical because as you burn fuel from a given fuel tank, or move the flaps and/or landing gear, the center of gravity (CG) shifts forward or aft.
That's me, on the ground, keeping track of things.
Remember, we test at the extremes of the weight/CG envelope. This requires us to control the CG during ground and flight conditions. We can move weight, in the form of water, forward or aft with the use of the water ballast system. This system is comprised of 48 barrels, each capable of carrying 460 pounds, connected by tubing to a pump. A computerized system tracks fuel placement, fuel burn, people placement, ballast, flap setting, landing gear position and water barrel quantity. The information is processed to display the airplane's current CG. We move water or specify fuel tank usage to configure the CG within the specified test requirements.
Our primary objective in Flight Test is to maintain the highest degree of safety for every type of testing we conduct. Some tests are high-risk by nature. During the preflight briefing on high-risk flights, we discuss risk mitigation and possible scenarios. We go through evacuation plans and crew responsibilities. We prepare to handle those scenarios and have procedures to minimize the risk. As Ground Operations Engineers, we are trained for fire fighting, first aid, CPR and defibrillator use. We are there to ensure that if something should happen in flight or on the ground while the doors are closed, there is someone in the airplane to direct and help people in an emergency.
As I mentioned, we'll go to the ends of the earth to get the necessary data for airplane validation. In fact, right now as I write this I'm getting ready to leave for Iceland. The winds just kicked up there and we have to go and get some autoland conditions at limit winds!