How hot is too hot for airliners to take off? How often do planes overfly hurricanes?

·2 min read

Is there a temperature that would not allow commercial jets to be able to take off?

– Curious flyer, Montana

Yes, there is a maximum temperature listed in the performance charts. If the temperature exceeds that reading, the flight cannot depart.

In some cases, it may be possible for the operator to contact the manufacturer and obtain the needed performance information. I experienced this one summer afternoon in Phoenix. The maximum temperature was 110 degrees Fahrenheit, and while we were on the ground, it exceeded that. Our dispatch office obtained performance information from Boeing for our specific flight, and that was sent to me, allowing us to depart after a slight delay.

At very high temperatures, the amount of payload an aircraft can carry can be limited. Offloading cargo and/or passengers is sometimes necessary as the hot air is not as dense, reducing available lift.

You recently wrote that it is possible to overfly a hurricane while staying away from the storm. Do many flights actually do that? Or are flights given paths well away from hurricanes, to eliminate even the remote chance of a mechanical failure necessitating descent into such a storm? How much longer do passengers spend in the air when flights take wide paths around storms?

– John, West Lafayette, Indiana

Yes, there are times when overflying a hurricane is a good decision. One example is a flight from Philadelphia to San Juan with a Category 1 hurricane off South Carolina. It could be the best option to overfly the storm.

There are contingencies considered, such as diversion airports. In the above example, Bermuda could be a good possibility, along with domestic cities not predicted to be in the storm's path, such as Jacksonville, Florida.

Normally, flights avoid the path of the storm. But in some cases, it makes sense to overfly them.

It's hard to say how much time is added to flight time by going over or around a storm. In some cases, the additional flying time is nominal, while in others, it can could be up to an hour.

Hurricane season is here: How do airlines deal with storms?

John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company, Safety Operating Systems. The views and opinions expressed in this column are the author's and do not necessarily reflect those of USA TODAY.

This article originally appeared on USA TODAY: Air travel: What temperature is too hot for a plane to take off?