Density altitude is the same as the indicated altitude in which scenario?

• A. 4°C at 5,500 ft PA
• B. 15°C at 7,000 ft PA
• C. -18°C at 9,000 ft PA
• D. -9°C at 3,000 ft PA

Answer: (A)

Density altitude is the altitude in the standard atmosphere that would have the same air density as the air currently at your location. It equals pressure altitude adjusted by the temperature deviation from ISA. When the actual temperature at a given altitude is exactly the ISA temperature for that level, the temperature correction is zero, so density altitude equals pressure altitude. If the altimeter is set to the local pressure (giving the indicated altitude), those two will align when the temperature is ISA, because the density conditions match the standard atmosphere at that level.

In the given scenario, 5,500 ft PA with a temperature of 4°C matches the ISA temperature at that altitude, so density altitude equals the pressure altitude, and thus it also matches the indicated altitude. The other cases have temperatures different from ISA, which means the density altitude would differ from the indicated altitude (warmer than ISA raises density altitude, colder than ISA lowers it).