Flying. It is something we are almost all familiar with, and yet I expect few of us have really sat back to appreciate the actual science of it. For the past 10 weeks we have been flying, not just a day or two a week but five or six days a week depending on the crew numbers and the weather options. We have worked out of two different locations in Greenland, both of which are on the western edge of this expansive island in the north.
For the past three weeks, we’ve been in Thule, Greenland. This US Air Force base has the northernmost paved runway in the region, offering service to points north (Yes, there are points north! ……. but those have gravel runways). The infrastructure here is good, complete with individual hotel rooms, as compared with the shared dormitory style rooms in Kangerlussuaq. Perhaps the most important part is that we get fresh vegetables with meals in the cafeteria. The lack of fresh vegetables for most of Greenland is remarkable as there really is no agriculture except a small amount of musk ox and reindeer (caribou) ranching. The Greenland diet is heavily slanted toward protein – fish and the meat of musk ox and reindeer.
The P3 is a workhorse of the Operation IceBridge field season. One thing that I’ve noticed, and had previously not appreciated, is that the blades of the propellers rotate. OK, before you say, “I knew that!” or, “No duh!” Take a look at the following photos. In the first photo in the hangar, the blades face the camera. The flat part is rotated towards the viewer. If you look closely, you can even see the point at which they are mounted.
Now, compare these with pictures taken from inside the plane. These are rotated to allow the propeller to push more air past the wing and increase speed – 90 degrees from the above picture.
This next video shows what you would observe of the propeller if you were inside the plane — just the gray windmilling of the propellers accompanied by a very loud buzz and whirr. This will also give you a view of how we move through the vast snow covered landscape. All of the missions are timed with respect to a ground speed of 250 knots for our instrument function (that’s 250 nautical miles per hour or about 288 miles per hour).
Part of the maintenance of the plane is a preflight inspection by the crew prior to any of the science crew or pilots arriving at the plane. This starts about 2 ½ hours before take off. Basic functions, such as checking the lights, seeing if the tail moves, etc. are all done prior to take off. When we do the night shift for firewatch, the shift ends as the crew arrives, so we are able to see the start of the inspection.
Additionally, the crew does an evening inspection of everything. Because the P3 is a workhorse of the NASA airborne science fleet, they keep the plane flying. The result is that parts wear out from time-to-time. The ground crew needs a little down time, and they get it during flight. Generally, they rotate off shifts with at least two always at the watch. Those who aren’t on watch take some down time — playing computer games or getting a few zzz’s in.
The last few days have been a bit of an overdose on Thule Air Base, however. The flight crew found something in a post flight inspection. A bushing delaminated in the propeller.
With the bushing gone the first thought was to fly the P3 back to the Wallops Island, VA test flight facility using three engines. Once there, with the parts, tools, and ground support, they could fix the plane. After considering the number of completed flights it was decided to close the season. The P3 stayed in Thule with the parts expected to arrive on Monday during the regular resupply of the base from the US. Monday came and went with no parts. The C130 air transport plane from McGuire AFB was full and could not take the 600lbs of parts and tools. Option B was for the parts to arrive today on the rotator. The rotator is a DC-8 plane that is about a 2/3 supply shipment and about 1/3 passengers for any staff changes for any position at the base.
Luckily, the parts and tools arrived. The crew went straight to work. As I wrote this, the crew took off and landed with the P3 on an FCF: functional check flight. This is a test to make sure that everything works. Good times! I’m waiting for the report on what they found…