IcePod Clears Hurdles and Takes to the Air
Monday:The morning briefing room was filled with layers of engineers and technicians from the civilian side, matched with pilots, navigators and air support staff from the Air National Guard side. Spanning the middle were the two Systems Project Office (S.P.O.) representatives. Adding new instrumentation and equipment to any aircraft requires intense scrutiny, but on a military plane there are extra rounds of reviews and sign offs required, and it is the S.P.O. office that is responsible for overseeing this final testing and approval. Specialists at avionics (aircraft electrical systems) and aerodynamics (air interaction and flow meeting the aircraft/pod) the first part of the week was theirs as they observed, measured, questioned and weighed equipment as it was installed in the aircraft, and prepared to monitor the in-air operation of the pod for turbulence, and potential aircraft/equipment interference.
The IcePod team arrived at Stratton Air Force Base with a carefully planned schedule of equipment installation and flight-testing. One day of install followed by two days of S.P.O. testing and then five additional days available for our own flight maneuvers to test the full potential of the pod and instruments. Inside the airport hanger crates of electrical wiring, connectors, tools and supplies were piled around aircraft 21094 the LC130 labeled ‘Raven Gang’ that was selected for the test flight. The biggest item on the floor was the 700 lb. crate containing the IcePod. The plan was to finalize the installation of the 350 lb.avionics (AV) rack located inside the plane, and then move straight to installing the arm and hanging the pod. By close of business Monday the goal was that the S.P.O. ground tests to ensure all the equipment was functional could be completed.
We were set back almost before we started. Rack pieces tightly matched to the curve of the plane body needed realigning, electrical connections needed adjusting, and by 7 p.m., the arm that would hold the pod was just being connected. Adjusted plans were agreed upon with an early morning return to add the pod and complete the ground check in the a.m. with a S.P.O. flight in the p.m. Snow was predicted over the evening but for flight the weather looked promising.
Tuesday: The morning briefing covered plans for a 10 a.m. flight time, which quickly slipped to a noon decision on the possibility of an afternoon flight. With the 500-700 foot cloud base predicted to rise to 1500 feet in the afternoon, this was not unwelcome news. In the hangar, electricians and engineers worked with thick ropes of cables taming them into place, floor pieces were notched and the pod support arm and special door secured in anticipation of hanging the pod, but delays continued. Before noon, a no-flight decision for the day was reached, as work continued at a slow but steady pace to prepare for to pod. The hope was that the ground testing could be completed before the close of day and Wednesday morning would bring the first round of flight testing.
By mid-afternoon, the pod was moved into place and fastened to the arm. The first S.P.O. concern was that the pod weight be within the approved limit of 400 lbs. Airport hangars have scales for weighing pallets of equipment but for this application a high degree of accuracy was needed. The first attempt showed a more accurate set of scales was needed. Each instrument, bracket, and set of cables added weight to the pod, so locating, calibrating and lowering the pod onto an accurate set of scales provided a few tense moments until the weight was established and S.P.O. clearance for test flights was provided.
Test Flights included turbulence testing for laminar (smooth) airflow done by installing tapered lines on the pod ends with sections of string inset to demonstrate airflow – 174 sections of string were added like a lion’s mane to the pod, and extending back behind the domed door. Exterior accelerometers were added to detect and monitor vibration on the pod as the group approached a 9 p.m. close to the workday. No matter what the status of the work the plane would be released from the hangar first thing in the a.m.
Wednesday: The weather dictated the day; socked in conditions with poor visibility meant no flights. S.P.O. ground testing was completed, but flying would be pushed off another day.
Thursday: High winds and driving rain arrived during the night with the morning briefing noting that although there was a high cloud ceiling and 3000-mile visibility, 25 mph winds and turbulence would keep us grounded early in the morning, but a 10 a.m. reassessment might allow a flight later in the day. Updates during the morning cited extreme turbulence for other flights forcing additional postponements. Mid-afternoon a decision was made to take up a minimal team to complete day one of inflight S.P.O. testing. On the runway engines are fired up, first 3 then 4 then 2 and 1, ready to go, but a problem with the Auxiliary Power Unit forced the mission to abort. Cancellation, and another day gone. As we headed out for the night we were warned that the APU issue could down the plane for up to two days.
Friday The hope is for at least one flight for this week, but we worry about the news on the APU. The morning briefing notes the APU seems to be holding and the first IcePod flight is a go! The plane is prepped; we are loaded onboard. Engine 3-4-2-1 fired up and we launch down the runway only to squeal to a stop. The domed door over the pod shows as not secure. The door is re-secured. A second attempt to move down the runway ends with the same results. Support is brought on-board and the door is reinforced for take off attempt #3.
10:56 a.m. we are up! The pod is deployed, lowering flawlessly. We begin the test flight at 5000 feet but lower to 2500 feet to move under the weather. The plan includes sets of cloverleaf maneuvers banked at 30 degrees to test GPS and lasers. The turns feel steep, and the ride is bumpy but after all the waiting we are happy to be in the air. There is no electromagnetic interference between the pod equipment and the aircraft, and the exterior accelerometers show a smooth ride for the pod. Test flight #1 for S.P.O. is complete, and everyone can head home for the weekend with a sense of accomplishment. In a week that seemed filled with adages (schedules are subject to change, everything hangs on the weather, anything that can go wrong will go wrong) at least we ended with …anything good is worth waiting for!
For more on the IcePod project see: http://www.ldeo.columbia.edu/res/pi/icepod/