Before every flight by Gulfstream test pilots, the flight test engineer conducts an exhaustive briefing on every imaginable detail. Obvious issues are weight, CG location, fuel load, reference airspeeds and so on. Less apparent are restrictions on operation of the specific airplane being used, such as airspeed or altitude limits that have not yet been cleared or the experimental status of equipment and avionics onboard. But the greatest emphasis is placed on the safety of the flight.
On the very first page of the briefing package and flight test cards that describe each maneuver in detail is a declaration of the risk involved in the flight. Details of the risk are described in the following "test safety hazard analysis" page. The TSHA, as Gulfstream calls it, is a brutally honest analysis of what could go wrong with the machine or the people flying it.
For my recent flight to see the new Gulfstream synthetic vision and enhanced vision system in action (see related article), the flight was declared to be "medium/low" risk, and the TSHA summary of the risk involved the enhanced ground proximity warning system and terrain.
The mission was to fly to Asheville, North Carolina, to see the new safety equipment in action in the dark and then again after the sun came up. It would not be a standard flight because we would actually fly at terrain and obstructions to experience the warnings the new system provided.
The safety analysis is based on FAA guidance provided in Order 4040.26A and FAA Advisory Circular 25-23. The "hazard" of this flight was as blunt as possible - "injury to the crew, damage to the aircraft structure." That certainly summed it up.
The causes of a potential hazard were: Loss of the ground proximity warning function. Unannunciated failure of the warning and caution alerts. False warning or cautions of terrain hazards. And hazardous or misleading information from the system.
The "effect" of these possible causes would be "no warning to flight crew of possible controlled flight into terrain situation, and the potential for unnecessary PULL UP maneuvers."
Now that the hazards had been identified and detailed, what would the Gulfstream test team do to prevent or minimize the risks? The first action would be a thorough preflight briefing covering all maneuvers and familiarization with the geographic area to be used. The briefing would also familiarize the crew with the airport environment, surrounding terrain and so on. The possibly hazardous flight toward terrain tests could only be done in daylight VFR conditions, and the pilots were familiar with the test site and EGPWS testing.
Finally, to minimize risk, the tests would be conducted with a third pilot or observer in the observer's station to serve as a monitor for approaching terrain and/or obstacles.
This test safety hazard analysis sheet was then approved and signed by the Gulfstream engineer in charge of the program, the test conductor and coordinator, the manager of flight test engineering and the test pilot who would command the flight.
All of this care and attention to safety detail was done for a flight in a mature G450 with the experimental equipment being display formats on one side of the cockpit. That equipment had been flown by the FAA, and final signoff was expected within days. But when you establish a culture of safety, consistency is essential. This flight went through the same safety analysis and approval system that every flight undergoes, whether it be tests with obvious risks such as the first stalls of a newly designed airplane, or something benign such as testing a new airborne telephone, which was in fact part of the test flight I made.
