Think like a Glider Pilot

Recently I was flying a Piper Arrow at 2500 feet in turbulent air. I was carefully maintaining my altitude with pitch and trim changes. It was a bumpy ride but it was nice watching the puffy cumulus clouds pass by overhead.

Then I began to notice my indicated airspeed was changing despite my unchanged engine settings. First, my speed would be up about 10-15 knots for a minute or so, then it would drop back down for another minute. The next minute it was back up.

Why was this happening?

I thought about it for a few minutes. The engine RPM and manifold pressure were constant, and my altitude was constant.

This could only be caused by updrafts and downdrafts! Yes, the same turbulent air that was creating those clouds was pushing the plane up every time I passed under one.

You can imagine my plane flying in that mass of rising air, and me correcting almost subconsciously to maintain altitude. As the air mass rises, I need to pitch down to stay at the same altitude. This is as good as descending as far as airspeed is concerned.

These updrafts are what glider pilots use to stay airborne and even climb without an engine. A single-engine plane is far too heavy to stay aloft on the updrafts alone, but they do offer us free airspeed which can save on rental or fuel costs.

But how do we take advantage of them?

First, there is terrain: When you have any kind of terrain plan to stay on the upwind side as much as possible. As the wind reaches rising terrain it will rise to go over it and this rising air provides a great updraft that you might be able to take advantage of by altering your course just a little.

Second is cloud streets: Puffy cumulus clouds are formed in rising air so alter course slightly if it will put you under some cumulus clouds. It may be bumpy but if you are between clouds the air will generally be descending to replace the rising air under the cloud. Glider pilots look for cloud streets, which are long rows of clouds that can provide an updraft over a very long distance.

Just think like a glider pilot and consider how the air around you is moving. Tailwinds get all the attention when looking for bonus performance from the environment, but a nice updraft can help any aircraft to go just a little bit faster for the same power.

 

Taxiing An Airplane

Taxiing an airplane is easy to learn once you get some muscle memory in place.

Taxi Controls

You may already know this, but for most airplanes, you taxi with your feet. Some large planes have a tiller but that is another story for another day. Your foot controls consist of rudder pedals that will control the rudder and, for many planes, also directly control the nosewheel steering. Continue reading “Taxiing An Airplane”

Accident Study: Focus on Takeoff

Today, January 25th 2018, a Piper Lance had an accident at Marathon airport in the Florida Keys. It veered off the runway during takeoff and came to rest in some trees. It is not clear if it had broken ground or not but it appears that it rolled at least 1000 feet before getting into trouble.

Local News Report

Based on the news report I have created this image of the approximate track of the aircraft.

 

According to the news story above the plane caught a gust of wind as it lifted off. Wind gets a bit funny during liftoff….

Here is the METAR from near the time of the accident:

METAR KMTH 251953Z AUTO 05018KT 10SM OVC047 22/16 A3019 RMK
           AO2 PK WND 06027/1854 SLP222 T02220161=

Quick quiz: If you are still rolling on the runway and a gust of wind blows from the left, how will the plane react?

The plane will want to turn left, into the wind. This is because the wind pushes equally on the surfaces of the plane, but the large vertical tail surface is far behind the main wheels, which will act as a pivot point.

Once airborne this is still true, but the wind will also push the plane as a whole to the right (causing a natural crabbing effect).

The passenger’s report makes sense in light of the METAR provided although it doesn’t explain why the wind wasn’t handled by correcting the controls.

The NTSB is on the job but we are left to speculate. Taking off in these conditions requires focus and a level of professionalism.

In this case, I am speculating that the runway centerline was being ignored. If this is the case the aircraft may have been lined up sloppily with the wide runway and during departure, the aircraft may have drifted steadily to the left. If the pilot was not correcting for this drift he may have found himself dangerously close to the edge of the runway at too high a speed to stop. Perhaps he tried to brake or tried to rotate to get out of the situation, but whatever the correction was, it didn’t quite work.

A pilot with a professional attitude would depart on the runway centerline and correct for drift to stay on the runway centerline through takeoff. This ensures a safe buffer with the edge of the runway and plenty of time to handle gusts.

IMPORTANT: Please read my disclaimer below about accident studies


 

This study and all accident studies are not meant to judge anyone, their actions, or their skills as a pilot. I do not claim to know what the pilot did or what he/she was thinking. The purpose of these accident studies is to better understand what causes accidents and how to avoid them. Comments and other points of view are always welcome as long as they are respectful towards everyone involved.

Takeoff

Taking off in an airplane is a fairly simple process, especially compared to landing. But this easy task can be filled with danger, especially because of complacency.

“Just throttle up and pull back!”

It might be easy to think of take off this way, but don’t lose your focus because it’s not hard to make a mistake that can pull the tire off the wheel or leave you stuck in the mud at the side of the runway. Continue reading “Takeoff”