christina j williamson

Test flights for ACCLIP – part 1

This week we started test flights for the Asian Summer Monsoon Chemical Climate Impacts Project. These flights are about 6 months before we start the proper campaign, and are designed for those of us who have not flow before on the GV aircraft that we’re using for this project. This way, any problems that we discover during the test flights, we have ample time to fix before the real project begins. Conveniently for me, the GV is based not far from where I work in Boulder, CO, so I can commute from home for the flights and pop back into the lab for spare parts as needed.

Before the test flights began, I loaded all my instruments into a rack designed for the GV aircraft. This rack is engineered to hold the instruments securely under any forces one can expect to experience on the aircraft and there are strict regulations governing how everything I use is secured to the rack. All of the instruments, electrical wiring, plumbing that brings air from outside the plane into my instruments, and computing equipment to control the instruments and record data, are subject to regulations that ensure they are safe to fly. It took quite a lot of documentation, checks and a few modifications of my equipment to get the certification required to allow me to install it on the plane.

My instrument rack, ready to load on the NCAR GV for ACLIP test flights


One of the more nerve-wracking moments of this mission so far, was transporting my equipment about 10 miles from my lab in Boulder to the NCAR Research Aviation Facility to go through final checks and then install on the plane. I enlisted a colleague to help me secure the rack full of precious instrumentation in the back of a small truck, and drive it over. The route passes through one of the windiest spots in Colorado (which is saying something!), on a none-too-calm day and we had almost a foot of new snow on the ground to reckon with as well! Thankfully, truck, instruments and people made it all 10 miles without incident. It was certainly an easier trip for me than for my colleagues who’d flow in from Germany

The RAF engineers checked over my rack, asked me to replace a few bits of hardware, and then signed off for installation on the plane. Installation itself was relatively straightforward, save for about 3 hour’s worth of bending stainless steel tubing in a ridiculously precise 3D shape to get from my rack to the inlet on the ceiling with minimum particle losses and within the allowed channels defined by aircraft safety regulations. My powers of spatial reasoning has never been so rigorously tested!

Instrument rack successfully install on the GC with the beginning of complicated plumbing to the inlet on the ceiling.


And now, the rack is secured on the plane and connected to the inlet that brings me the air I need to sample. The RAF engineers have signed off to say everything is ship-shape (plane-shape?) and safe to fly. I’ve done my egress (safety briefing, a bit like an in-depth version of the safety announcements at the beginning of commercial flights, but a lot more hands-on) and am ready for test flights!