Twombly stated that pumping the throttle "was a departure from...the flight manual." Suggesting that pilots ignore the procedures in the manuals is not good advice. If an aircraft was damaged in a fire on startup, I'm sure the insurance carrier would be very interested in the pilot's method.
Vince D'Angelo
Naples, Florida
An Easier Way To Navigate
Hurray for Budd Davisson! His article, "In Defense of the Compass" (Feb- ruary 2001), is a breath of fresh air. However, the in-flight use of the chart can be even simpler than Davisson describes. Once in the air, we can drop the use of miles and simplify the problem. Only time matters in the air - time to fuel exhaustion.
I do most of my flying in open cockpit aircraft, where you cannot set down the chart and write on it. Let go of a chart and it is gone. So, I use techniques taught me by several older gentlemen; these techniques require no writing and very little mental math.
To explain how I use this method, let's say we are in Airplane A, which cruises at 120 knots and will fly for two hours with a suitable fuel reserve. The leg today is due north for 200 miles. The wind is 045 degrees at 15 knots, making for about 10 kt each headwind and right crosswind. I mark the chart with a course line and just two pieces of information: magnetic course and expected time since takeoff.
To maintain my course, I use the compass just as Davisson describes in the article. I can run the wind calculation on the E6B or I can estimate it. Today, I'll start out with a 5-degree crosswind correction for a heading of 005 degrees. During preflight, I calculate the time the flight should take, in this case one hour and 49 minutes, well within the two-hour fuel limit.
To track my progress along the course, I use elapsed time since takeoff. Rather than mark each checkpoint with the expected elapsed time, I put marks every 10 minutes along the course line. At an airspeed of two nautical miles per minute, the time ticks will be 20 nm apart.
As I fly along the course, I look first at the clock and read how many minutes have elapsed since takeoff. I then look at the chart and find that many minutes on the "time scale," interpolating between the tick marks as necessary. Then I look at the ground, com- pare where the ground says I am with where the chart says I should be, and fix my position to correct for any deviation. Near each 10-minute tick mark, I compare the expected time with the actual time and figure how many minutes early or late I am.
There it is: a simple technique for navigating VFR. No writing or heavy calculations in the cockpit and, most importantly, you are always thinking of time in relation the flight time left in the fuel tanks.
John McMurray
Burkburnett, Texas
Help Finding A Headset
Thanks for the informative article by Elizabeth Tennyson on selecting headsets ("How to Buy a Headset," April 2001). I was looking for a headset recently and found at least 37 different models offered in Sporty's cat- alog alone. In order to simplify the comparison process, I used my Excel program to develop a spreadsheet to sort and compare them. By sorting headsets by price range, weight, and NRR, I greatly eased the task of selecting a set for my needs. The one factor that Tennyson did not cover was the significance of whether or not a headset is TSO'd (Technical Standard Order). How important is this designation?
Fred Ingersoll
Via the Internet
The Value Of TSO
When a headset is TSO'd, it has received approval as having met design and manufacture standards set by the FAA or the Joint Aviation Authorities, which is Europe's aircraft certification body. The designation is your assurance that the headset meets aviation safety requirements, such as having vented diaphragms.
While a TSO'd headset has met specific minimum aviation standards, manufacturers are not required to put their headsets through the sometimes expensive and time-consuming certification process. Many excellent aviation headsets are available both with and without having been TSO'd.
Elizabeth A. Tennyson
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