Too Hot to Fly

Q: Flying from Mexico City, several passengers were bumped from our flight We were told it was too hot for the plane to depart fully loaded. Can this “it’s too hot to fly” explanation possibly be true? Is an airplane so delicate that a few degrees change in temperature renders it unable to fly?

The author once got stranded at the airport in Cuzco, Peru, in a similar situation. Increasing temperature and altitude negatively affect an airplane’s performance by decreasing the density of air, though it’s not anything so over-the-top as being unable to fly. Rather, a plane may no longer meet the very strict performance requirements for a runway. These include the distance needed to stop following the rejection of a takeoff at high speed, and required clearances over obstacles in the departure path, which would be important in the event of engine failure. All of this is figured out beforehand by the flight planners and dispatchers, and a maximum takeoff weight is determined. Mexico City sits at about 7400 feet, and is a great candidate for a performance hit.

This is one of those areas where airlines really could do themselves a favor by offering more coherent, technically explicit explanations to passengers rather than churlish announcements like, “it’s too hot to fly.”

---

This Q&A is part of a collection that originally appeared on Salon.com. Patrick Smith, 38, is an erstwhile airline pilot, retired punk rocker and air travel columnist. His book, Ask the Pilot (Riverhead) was voted “Best Travel Book of 2004” by Amazon.com. Patrick has traveled to more than 55 countries and always asks for a window seat. He lives near Boston.