Graeme J W Smith

Archive for January, 2011

Sat morning – 290 at 7 knots, 15F/-10C, 10 Miles plus visibility – we have Visual Flight Rules and are just in cold weather operating limits. Let’s try for breakfast in Fitchburg, MA followed by some accelerated stalls and landings. Wonder what Greg my instructor will have in mind? I take him in the Flight Plan I have prepared. He reviews it. OK’s it and off we go.

FANTASTIC smooth air – clear for 50 miles in all directions blue sky flight, first down on freshly plowed runway 32 at Fitchburg. Couple of circuits – in for breakfast, some more circuits then back to the Scituate Training Area for accelerated stalls and power on stalls. Back down in Providence. 3.6 hours and 7 take offs and landings in the logbook. The nav plan worked out beautifully, VOR tracking was right on the money and we even remembered to close our flight plan with Flight Service before they came looking for us. It just doesn’t get any better on days like this when the aircraft performs so well in the dense cold air.

“Wet” aircraft rental for flight out and back – $135 per hour
Instructor $55 per hour
(Out and back was about 1.5 hours)
Breakfast for two with generous tip – $25
Landing fess – remember that generous tip? No fees.

Total $310 / 2 = $155 per breakfast.

So I’m preparing cross country flights and laying my plotter on the sectional chart. To my seagoing navigation eye it looks like the parallels of latitude are slightly curved instead of the straight I’m used to. I look in the title box on the chart. No mention of the projection used. I dig around and find it is Lambert’s Conical. A little more reading.

The Mercator projection that used to hang on the elementary school room wall – latitude and longitude lines are straight, parallel and at right angles to each other. The distortion at the poles is horrific and a Great Circle route is drawn as a curved line. Charles Lindeburg figured this out in the week before his flight across the Atlantic while studying navigation for his trip in the local library. He prepared a series of courses on his school room map of the Atlantic and flew for an hour at each heading – adjusting slightly on his chart every hour and (rather amazingly) found Ireland and then Paris. This is the practice at sea – where you move relatively slowly and have time to figure this stuff out and alter course on the distorted paper chart every few hours. There are some other useful sides to Mercator projection for plotting star and sun sights which is why it is still used at sea.

But as flying speeds increased this method became a PIA and the Lambert conical projection was used for flying. A line drawn between two points in a straight line is essentially a Great Circle route and this avoids the need to fly constantly changing courses across the distorted Mercator chart. But there IS a gotcha – because of the way the projection is laid on the paper – Yep – the LATITUDE lines on sectionals ARE slightly curved. Lambert Conical Projection at work. But an upside to Lambert (as with Mercator) is that you can use the LATITUDE (but not Lon) scale as a Nautical Mile scale.

It actually gets alluded to on page 4-42 of the Jeppsen Private Pilot Book book without going into detail.

More about it – two fifths of the way down this page where the Civil Air Patrol discuss how to draw the correct slightly curved lines to grid a sectional for Search and Rescue Operations.

and more at Wikipedia

Dawn lesson – A cross country trip (meaning more than 50 miles) from Providence to Chester in Connecticut. Principal part of the lesson – pilotage – meaning looking outside to see where you are compared to the chart. 10 min pilotage prep and go. Scored practical test standards first trip out. Not exactly hard when you can look down on everything from 4,500 ft compared to trying it from sea level in a boat!

Chester is totally cute. Like back in time to the 1950’s with lots of old but beautifully kept airplanes under the open sided hanger. Spot the white picket fence at the far left end!

Runway needed short field landing technique and short field take off to get back out. 34 mins to get there and 15 mins to get back by staying low in the small headwind on the trip out and going high for the strong tailwind on the way back.

Blew my first landing at Providence and went around. Greased the second one! Back in the groove for landings – I hope!

Saturday briefing – pick a suitable airport for the conditions that you would like to fly to for breakfast!