I was discussingis this deployment with members of the other Youngstown crews and I was lamenting about the lack of flying since we've been here. But during the discussion I realized that our crew will have flown 90 hours in the month of June alone (we have one more mission this month). The max in a 30 day period is 110 so we actually have flown a ton of hours!!! It illustrates the differences in perception when you fly different aircraft that fly at different airspeeds.
Not all planes fly the same types of airspeed either. The C-5, KC-10, C-17, and other turbojet aircraft (including your commercial ones such as the 737) all fly using Mach numbers, which is the ratio of the object traveling through the air divided by the speed of sound. On a standard atmospheric day of 15 degrees Celsius (59 degrees Farenheit) and sea level pressure, the speed of sound is roughly 761 mph. A C-5 routinely cruises at Mach .77 or .79 (the Air Force prescribes .74 to .77, but unless they are going to install a tracker that transmits the speed, crews are gonna go peddle to the meddle). So a 5 flies around 585 mph on average.
In the Herk world we fly cruise profiles using TAS (true airspeed). True airspeed takes into account air density and compares it to sea level density and computes a number. All fuel planning takes into account true airspeed because you need this speed to determine how winds will affect your fuel burn. The Herk flies around low level utilizing indicated airspeed, which is what it says it is: the speed detected by the pitot tubes and read off the gauge. The C-5's use something called calibrated airspeed, which is actually a computed airspeed based on indicated, but then corrected for compression errors as it flows into the pitot tube. The C-5 has spanky central air data computers that utilize this speed for things like autopilot, augmentation (power assist for the flight controls so you can account for the air pressure on the flight control surfaces based on airspeed), and navigation.
You can convert all of these speeds into another, but we don't. Herks cruise at roughly 290-310 true and that is what all of our performance numbers are based on. We don't even think in terms of Mach as we fly at much lower altitudes. C-5's use TAS to determine groundspeed, which requires TAS to calculate how wind direction and airspeed relate to the actual speed of the aircraft in reference to the ground.
A side story about groundspeed before I relate how different flying the Herk is than a C-5. I was once flying a Cessna 172 between San Angelo and Del Rio, Texas. By jet it's a 20 minute flight and about 157 miles By Cessna it's about an hour and a half. I had been flying for ten minutes or so when I noticed a yellow pickup to my right driving on highway 277 below me. Not thinking anything I kept flying along and hit a little turbulence, which almost rolled me over on my back. I called up center and asked if there was any forecast turbulence at my altitude since the dumbass at the flight service station didn't mention any when I went in and got my weather brief and filed my flight plan. Houston replies that there is moderate turbulence from 4,000 to 20,000. Wow!!! I'm at 6 and I'm about to get completely fracked and end up on some crash report. So I terminate flight following and tell the controller that I'm going down to 3000. I get down there and I'm being bumped by the roiled air coming off the desert rocks below me, but it was much more comfortable. It killed my groundspeed though. Instead of doing a 100 mph over the ground with an airspeed of 100 mph indicated, I was now doing 54 mph with an airspeed of 104 mph. The yellow truck was beating me to Del Rio!!! Talk about humiliating. I actually thought about landing on a dirt road and hitching a ride!!!!
The Herk flies lower than jets. We are routinely at 18-20,000 feet. A C-5 is routinely at 29-35,000 feet. BIG difference!!! Up there you catch the jet stream and if your headed to Europe in the winter flying over the top you can make it from Delaware to Germany in 4.5 hours. Never in a Herk will that happen unless it's a sci fi movie. Many a night flying over the Atlantic on the NATS (North Atlantic Tracks), or airways that all aircraft flying to Europe follow, I have routinely seen groundspeeds in excess of 600 knots!!!!!!!!!!! Craziness!!!!!!!!!!! You get to the gulf or Europe in no time. If your headed toward the gulf your screwed coming back.
In a Herk, we see grounspeeds of 300 knots. I just realized I mentioned the knot, or nautical mile, and haven't defined it. We don't use mph flying big guys, we refer to the standard nautical mile. A knot equals 1.151 statute miles thus a knot is a faster unit of measure of speed. Often our groundspeed is lower than 300 because we're getting beat up by the winds at the lower flight levels. Many times we're getting hit with a headwind, which reduces our groundspeed. Rarely do you get a good tailwind, which speeds up your ground track.
How does this all fit with my opening paragraph? When your groundspeed is substantially lower at lower altitudes, it takes you longer to get where your going. If your out on a C-5 mission for two weeks with min ground times between flights and maximum crew duty days, you can fly 90 hours in those two weeks and be gounded because you will most certainly go over your maximum flying hours in a 30/60/90 day period because of how trips are scheduled in strat airlift. In a Herk you can build up hours like crazy, but our days are shorter so you can't fly as far. Your still flying 90 hours, but you do it with shorter legs and a lot more of them in the same period of time. A lot of times it takes you two and three days to get somewhere. Into the gulf it takes three days via Herk, one via C-5. In the Herk you crew rest in St. Johns, Newfoundland, Prestwick, Scotland and Souda Bay, Crete. There are other routes 130 units take to position/deposition into and out of the war zone, but this one is pretty popular.
I've only flown 13 days for June and I have 75 hours. I have been off the other 17 days or so for the month, or will be since the month isn't over, so it feels like we're not flying. Also the longest day I've had was 16 hours, which I've only had three of those so it's not hard flying. In the strat airlift world your days are routinely 20 hours or more long, with several 26 hour days on missions. Our max day length with our current crew compliment is 16 waiverable, by US, to 18. It takes 11 hours to get from Ramstein, GE to Djibouti and you can't do it all in one leg because of gas requirements. You fly an occasionally long leg, lots of short legs and days with multiple hops that add up to more hours because you take longer to get there. I hope that we average 90 hours a month as that would make the time pass, but I wish we were flying more days out of the month with shorter legs. Not going to happen because going into the middle east on a Herk from Europe = a sore ass from sitting in the seat for long hours droning over the sandbox!!!!
There is another drawback to flying at lower altitudes as well. I have never flown in so much icing in my entire flying career. In the C-5 you don't have anti-icing capabilities except on the engines so when you encounter ice you climb or descend your way out of it. In the Herk you have anti-ice on the wings, tail, and engines so you just fly through it. It's a little disconcerting to watch ice build up on the wiper blades until it's so thick you could add Kool Aid for a slushy!!!!!! If your flying in ice in the summertime, that must mean your flying through a line of afternoon thundershowers. No getting above them so we have to penetrate them quite often. That's where our low power, color radar earns kudos!!!!!!! We just pick our way through the giant clouds. Sometimes the clouds look really ominous, but the returns indicate that the rain velocity is very slow and so we can fly right through it. I have posted a few thunderstorm pics on Picasa and I will be taking more. I hope all of you can see the Picasa album. If not comment on the blog and I'll fix it.
Tomorrow we're going to the cemetary and Belgium. I'll take plenty of pics for you.
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