Updraft Sends Flight Crew Above Their Clearance Altitude On SID

Have you ever gotten caught in a strong updraft? Here's what can happen...

Flight Crew Report

The following NASA ASRS report demonstrates how updrafts can interfere with your ability to maintain an IFR clearance altitude. As you read the report, think about which physiological illusion you'd expect to occur during an encounter like this...

During our initial climb, it was apparent that towering cumulonimbus was going to be a factor along the SID which was issued. We asked for and received a heading in an attempt to avoid the clouds. We also wanted a climb to attempt to avoid the clouds due to the expected turbulence.

During the turn and initial level off, we entered into a cumulonimbus type cloud with moderate turbulence and updrafts. During this time, we couldn't level off at our assigned altitude of 9,000 feet and reached a max of 10500 ft. We immediately lowered the nose and descended back to our assigned altitude. We received NO TCAS TAs or RAs. No further issues were experienced. During the updraft, we focused on flying the plane and let ATC know what caused the deviation after we were out of the weather.

Developing Stage Of Storms

As you lift air from the surface, it cools. The temperature keeps dropping and approaching the air's dew point. Once it hits the dew point, moisture starts to condense out of the air, forming clouds. This altitude is the convective condensation level. It's the lowest altitude that condensation occurs because of convection from surface heating.

As moisture condenses out of the air, it releases energy. (It takes energy to turn water into a gas, and that energy releases as heat as the gas condenses back into water.) Now that moisture is condensing out of the lifted air, it's much warmer than the surrounding air. As it rises, that temperature gap grows, and the air continues to accelerate upward, forming a strong updraft. This creates a towering cumulus cloud, or TCU. And with that, you have the developing stage of a thunderstorm.

Boldmethod

Physiological Risk: Elevator Illusion

One of the most challenging things about flying IFR in the clouds, is that there's usually some turbulence as well. Elevator illusion happens when you catch an updraft, and your plane is abruptly accelerated vertically. Even though your plane is most likely in straight-and-level flight, you feel like you need to push the nose forward, entering a dive attitude.

How to prevent it: Maintain a strong instrument scan pattern in turbulence, and if the updrafts and downdrafts become so strong that you are unable to maintain altitude, fly the attitude indicator, keeping your wings straight and level.

Boldmethod

How Much Can You Do?

If you find yourself in a strong updraft, the best thing you can do is focus on flying the airplane. Keep your wings level, decrease power, and pitch as necessary. If you have time, let ATC know why you're unable to maintain altitude, but only after you're sure you can maintain positive control over the airplane (Remember: Aviation, Navigate, Communicate).

The best thing you can do is to work with ATC as soon as you see the weather, and avoid towering cumulus clouds if at all possible.

Has This Ever Happened To You?

When was the last time you experienced a noticeably strong updraft or downdraft under IFR? Tell us in the comments below.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and a First Officer on the Boeing 757/767 for a Major US Carrier. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), is a former pilot for Mokulele Airlines, and flew Embraer 145s at the beginning of his airline career. Swayne is an author of articles, quizzes and lists on Boldmethod every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel.

Images Courtesy: