The phrase "at a certain altitude" is correct and usable in written English.
It can be used when discussing specific heights or elevations in contexts such as aviation, geography, or scientific research.
Example: "The aircraft maintained a steady flight path at a certain altitude to ensure passenger comfort."
Alternatives: "at a specific height" or "at a defined elevation."
"I was struck by the fact that, at a certain altitude, there were a lot of dark grey trees, mostly firs, and also meadows of a lively green.
The craft has antennas measuring 30 metres and extending in four directions, which at a certain altitude above Earth could cause problems.
At a certain altitude, the mind carries on an interesting self-interrogation: Am I still sane?
"Maybe they are not really surface structures, but tenuous clouds of hot gas at a certain altitude," he says.
The traditional SAR system often operates along a straight path at a certain altitude with respect to the ground plane[1 4].
In this mode, the platform moves along a circular path at a certain altitude with its antenna beam pointing fixed perpendicular to the flight velocity away from the center of the circular trajectory, the result is a moving antenna footprint that sweeps along an annular terrain.
Instead, a keyboard is used to issue instructions, the way a pilot onboard might instruct an autopilot: climb to a certain altitude at a certain rate, level out, roll the plane to a new heading, proceed to a certain point and make a turn in a different direction; land on a particular runway at a certain airfield.
Above a certain altitude, the atmosphere becomes so thin that a human body ceases to function properly.
Sometimes it's just about hiking to basecamp or getting to a certain altitude and turning back.
Helicopters cannot fly above a certain altitude.
A Volcano Pass from the United States Forest Service (USFS) is required for activities above a certain altitude.
