Definition
An item included in a Transcribed Weather Broadcast (TWEB) when the density altitude at an airport is at or above 1,000 feet higher than the airport's actual elevation. It alerts pilots to reduced aircraft performance caused by the thinner air the engine, wings, and propeller are working in.
Plain English
A short notice in the broadcast that warns you the air at this airport is performing as if the field were much higher than it actually sits. That means weaker takeoff power, longer takeoff rolls, and slower climb.
Context Anchor
You would encounter this while listening to or reading an Alaska TWEB before a flight, especially when planning departures, climbs, or operations from higher-elevation or warm locations.
Derivation
Density altitude is the pressure altitude corrected for non-standard temperature -- in plain terms, the altitude the airplane 'feels' it is flying at based on how thin the air is. The 'statement' part is simply the spoken advisory tucked into the broadcast.
Why Pilots Care
High density altitude reduces aircraft performance, affecting takeoff distance and climb rate, which is critical for safety in mountainous or hot areas.
Analogy
It is like the airplane asking, “How high does this air make me think I am?” Even if the airport is not very high, hot or thin air can make the airplane perform like it is taking off from a much higher place.
Grounding Statement
If the air is warm or thin, the airplane has less air to work with, so the density altitude statement warns you to expect weaker performance.
Intuition Check
Do not read “density altitude statement” as just a comment about airport elevation. It is about aircraft performance in the air conditions, not simply the height of the airport.
Example Sentence 1
The TWEB included a density altitude statement for the airport, so the pilot reworked the takeoff distance before loading passengers.
Example Sentence 2
Listening to the TWEB, the pilot noted the density altitude statement and decided to wait for cooler temperatures before departing.