Heat wave reducing aircraft performance, raising aviation safety concerns

Extreme heat can disrupt flights even when skies are clear. Fox5 Vegas reported on August 5 that hotter air can reduce aircraft takeoff performance enough to trigger delays, payload cuts or cancellations in some conditions. The issue has surfaced again as Europe’s heat wave pushed temperatures to record levels this week, including 41.2 degrees Celsius in Bad Deutsch-Altenburg, Austria, on August 5, according to GeoSphere Austria as reported by Reuters. ### Why does heat matter if the weather looks fine? The FAA says density altitude has a “significant and inescapable” influence on aircraft and engine performance. In the agency’s guidance, density altitude is pressure altitude corrected for nonstandard temperature, and higher density altitude means thinner air and degraded performance. Hot, high and humid conditions can turn a routine takeoff or landing into an accident, the FAA says. (fox5dc.com) SKYbrary, the aviation safety knowledge base supported by international industry and regulatory participants, says heat affects operations regardless of airport elevation. Its hot-weather guidance says higher temperatures increase density altitude, which in turn can impose a “substantial performance penalty” on takeoff. ### What changes for an airline crew on a very hot day? (faasafety.gov) Before departure, pilots and airlines calculate whether an aircraft can safely take off using the airplane’s weight, the airport’s elevation and the outside temperature, retired Delta Air Lines captain Alan Price told the Associated Press report carried by Fox outlets. When temperatures climb, airlines may have to remove passengers or cargo, carry less fuel, or push departures to cooler hours. (skybrary.aero) Las Vegas has provided a recent example. The AP report said Delta Air Lines asked for volunteers to leave a flight during an excessive heat warning in July 2023 because of weight restrictions tied to the temperature, and the flight was later canceled after passengers spent hours aboard the aircraft. ### Is this only a problem at high-altitude airports? (taylorvilledailynews.com) The FAA says high-elevation airports in the western United States are especially exposed because aircraft are already operating in thinner air. Its guidance says high temperatures can make safe operations impossible at some airports during parts of the day, and that even lower-elevation airports may require weight reductions. (usnews.com) SKYbrary gives a simple illustration: a sea-level airport at 45C would have an approximate density altitude of 3,600 feet, before accounting for humidity. That means heat alone can create conditions that make an airport perform more like one at a much higher elevation. ### Does this become a safety issue on the ground too? IATA flagged “hot cabins” as a safety issue in guidance published in June 2024. (faasafety.gov) The airline trade group said extreme heat inside aircraft cabins can cause fainting, collapse or heat exhaustion, particularly when ground power units or the auxiliary power unit are not functioning. EASA, the European Union Aviation Safety Agency, says climate change is expected to increase the duration and intensity of heat waves in Europe, North America and Asia, decreasing aircraft takeoff performance and creating health risks for passengers and personnel. (skybrary.aero) EASA says those events can lead to operational disruption with safety and economic effects. (ic.iata.org) ### Why is this getting attention now? Reuters reported on August 5 that Austria set a record high of 41.2C in Bad Deutsch-Altenburg near the Slovak border, citing GeoSphere Austria. EASA says Europe has been warming twice as fast as the global average since the 1980s, and that longer, more intense heat waves are one of the hazards aviation now has to plan around. (easa.europa.eu) Fox5 Vegas published its report on August 5, and the FAA, IATA and EASA guidance it echoed is publicly available now for travelers, airlines and airport operators monitoring late-summer heat events. (fox5dc.com) (wsau.com)