How does heat affect aircraft?

[mny]

Going to be over 100 degrees in much of the country this weekend. And the planes will be on hot pavement. Can anything melt or be damaged? Other than more turbulence, what else can I expect?

As I get closer the anxieties and old, bad mental constructs get stranger :thumbsup:

[Captain Hutch]

:tiphat:Dear MNY,

Most components outside of the flight deck and cabin are built to withstand extremely high temperatures so the triple digit temperatures that we have been experiencing as of late do not have a direct effect on the aircraft as it sits or taxis on the ramp.
Some things that are affected are the capability of the air conditioners to cool the cabin. The auxiliary power unit (APU) runs the air on the ground with possibly the help of idling engines, which sometimes still isn't enough to cool an aircraft full of passengers. That's why it helps to keep the window shades down and the air nozzles above the seats open.

Hope this helps,

Hutch

[Aurora]

Also warm temperatures make the air "thinner", so you need more power for takeoff (if I'm not mixing things up).

I vividly remember a trip in a Cessna 172 with a friend in February. It was around minus 16 degrees outside. As we did some touch'n'go rounds - he proclaimed in the outmost joy "OH MY GOD IT PREFORMS LIKE A F16" :lol:

[MathFox]

Also warm temperatures make the air "thinner", so you need more power for takeoff (if I'm not mixing things up).

You need more (true) velocity to get the same amount of lift when the air is hot (less dense). On the other hand, because the air is less dense, there is less oxygen to burn, which reduces the available engine power.

[Aurora]

Yes what MathFox said! I just can't put it in proper words :tongue:

[Barb-SAN]

I don't know if the original poster has a choice of seats when boarding (i.e. if flying SWA) or not. When flying cross-country, I try to pick the side of the plane opposite to where the sun is as it tends to be slightly cooler, and you can open your window shade and not have the sun shine in directly on you.

I'd also suggest buying some extra bottled water to bring with you on the plane. You want to be sure to stay hydrated, and that way you don't have to wait for beverage service.

We passengers in the A/C have it much better than the poor rampers who will be out there on that hot pavement loading your luggage onto the plane, driving the tow trucks, fueling the plane, directing the planes, etc. I wonder if there's any provision for them to work fewer hours when the conditions are extreme? There have been "excessive heat warnings" posted on weather.com for a few days now.

I imagine Capt. Hutch has fond memories of doing the preflight walk-arounds in mid-summer on the East Coast. ;)

As far as aircraft performance in heat...ah, I remember struggling in ground school to understand the density altitude calculations. :( http://en.wikipedia.org/wiki/Density_altitude

Basically, high, hot, and humid decrease aircraft performance. Runways are built longer in places like Phoenix and Denver to account for those factors. Temperature also factors into the weight and balance calculations (how many passengers, how much fuel and cargo). As passengers we aren't usually aware of any of that. Though once leaving San Diego I was on a plane that pulled off to one side of the taxiway and sat with engines running for 15 min. Pilot said we had to burn off fuel because we were overweight! (What a waste...!).

[mny]

Thanks for all the quick responses. I don't mind being hot, or getting delayed, TSA or anything people normally complain about as long as I land safely :hyped:

[Barb-SAN]

To add a graphic to this thread, since Friday had some record-breaking heat, check out these heat indexes (factoring in humidity). My sympathies to any of you who have to work outside in those temperatures.