The Association of Flight Attendants (AFA), which represents 50,000 flight attendants at United Airlines and 19 other carriers, is getting into the heating and cooling business, so to speak.

Ditto for some 15,000 flight attendants at Southwest Airlines who belong to Local 556 of the Transport Workers Union.

On Wednesday at an event at Reagan National Airport in Washington, D.C., representatives from both AFA and Local 556 will unveil a new app they have jointly developed called "2Hot2Cold," now available for download by both airline crews and interested passengers for use on both iOS and Android devices.

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As the name suggests, the app allows users to file reports on airplane cabin temps deemed unacceptable by passengers flying in a particularly hot or cold cabin or by those stuck in overly hot or chilly planes while at the gate deplaning and boarding passengers — the process known as a "turn" in the airline industry.

A spokeswoman for AFA today said airplane crews in recent years have become increasingly concerned about cabin temperatures — a matter that has gotten buried amid all the other factors increasingly impacting airline travel today.

Ideally, flight attendants at AFA and Southwest would like to see the United States Department of Transportation establish a specific set of guidelines for acceptable cabin temperature. The 2Hot2Cold app is part of that effort.

The new app allows users to send information on cabin temperature, specific flight details, plane location and even the tail number of an aircraft to a central data collection point. The information then will be collated and presented to the DOT to support AFA's and Local 556's efforts to establish parameters for cabin temperatures.

Many factors, of course, affect a plane's cabin temperature, including the effectiveness of various ground ventilation systems aircraft connect to at airports across the country, as well as the ventilation system on any given airplane.

But tens of thousands of flight attendants believe that, despite the many variables, having a set of standards backed by the DOT will help in addressing an important problem of some complexity affecting the health and comfort of huge numbers of crew and passengers.

In any event, the new app will certainly give aviation geeks another means to help bring about change in the airline industry.

As part of the rollout of the new app, leaders at AFA and Local 556 plan to distribute 60,000 keychain thermometers this week to flight attendants at 23 airlines based in the United States.

So if you are flying in the weeks and months to come, expect to see a lot of thermometer checking.