Page 50 - Volume 15 Number 8

ON FINAL by David Miller
Maximum
Performance
No, this is not an article about drugs for male sexual enhancement. That is a private matter between me, I mean you, and the doctor. But I bet I got your attention with the headline.
Instead, this is a piece on how, as pilots in command, we plan to achieve maximum range and performance from our flying machines. Let me demonstrate with a recent round trip flight from Dallas- Addison (KADS) to Elizabeth City, N.C. (KECG) in a Citation Mustang.
With 5,000-plus hours in his logbook, David Miller has been flying for business and pleasure for more than 40 years. Having owned and flown a variety aircraft types, from turboprops to midsize jets, Miller, along with his wife Patty, now own and fly a Citation Mustang. You can contact David at davidmiller1@sbcglobal.net.
of headwinds and inadequate fuel reserves. Ouch. For me, it meant a possible en route stop at Raleigh-Durham.
But I wasn’t giving up yet. The G1000 system has a great integrated feature that shows fuel over destination based on the flight plan. At the halfway point over Memphis, I wanted to see at least 700 pounds, knowing that my fuel burn would increase during the descent into KECG. The number I saw was 600 pounds. Not too comfortable, especially since I was unfamiliar with area around the destination, center habits of early descents, etc.
But I had a thought. The Mustang has long-range cruise charts that precisely show fuel burn and true airspeed for many altitudes. In most cases, there is very little difference between max cruise and long-range cruise. But I didn’t need much to get to my “comfort range.” Just 100 pounds. So I began to reduce power by less than one percent and watched as the magic “700” appeared on the fuel calculator. That’s why they call me pilot in command. We landed with 690 pounds of fuel.
As usual, on the return, the possible tailwinds had vanished, leaving me with the same challenge. I had another idea. Although we had topped off at KECG in the warm afternoon sun, I called the FBO early the next morning and asked them to see if they could get just a little more fuel in those cool wings. They got 60 pounds. We landed in Dallas with exactly 600 pounds. Sometimes it’s the little numbers that are important.
Fly safe.
Here are the numbers: Distance Cruise Altitude Temperature Weather Weight Forecast winds Minimum fuel at landing
1,037 nm
FL410
ISA -04 at FL 410 VFR
Max takeoff
+7 tail wind
600 pounds
Predictions from flightplan.com indicated the fuel would be close with 566 pounds remaining at destination. But as we know, not all things go as predicted. We departed out of Dallas at 0630, an excellent time of the morning in a busy terminal area to get unrestricted climbs that would reduce our total fuel burn. As in all jets, the Mustang’s engines love temperatures below standard. And at lighter weights, you often have to reduce power from the cruise detent in order to stay below MMO (max operating mach at cruise). But today, we were heavy. What I neglected to notice on this day was that the temperatures in the climb started out at ISA+17. We were just too heavy and hot to make FL410 and had to settle on FL390 initially. That meant my total fuel burn would increase slightly. A little post-flight research told me that the standard paper briefing at flightplan.com gives you temperatures at altitudes that are close to your selected cruise level. But a few clicks on their Web site will educate you with info on many additional altitudes on the way up. Had I done this, I would have known that climbing straight to FL410 would not be possible today.
In addition, Mother Nature was not cooperating. Actual winds were not as predicted and turned out to be 25 to 45 knots on the nose all the way to KECG. On the Memphis center frequency, a Chicago-bound American flight requested a diversion to Indy because
48 • TWIN & TURBINE AUGUST 2011