The phrase "a gentle descent" is correct and usable in written English.
It can be used to describe a gradual or soft decline, often in a physical or metaphorical context.
Example: "The hikers enjoyed a gentle descent down the hillside, taking in the beautiful scenery along the way."
Alternatives: "a smooth decline" or "a gradual drop."
Moody used autopilot to glide the plane into a gentle descent.
Just before the summit, the trail turned left, segueing into a gentle descent through stands of young beech trees, their new leaves so green they glowed.
According to the author's memoir, "A Fish in the Water" (1993), the Llosas "had been well-off and possessed of aristocratic airs" before a gentle descent into the middle class.
Barry agrees there could have been a gentle descent.
He drew back the throttle just enough to establish a gentle descent and waited until crossing the runway threshold before he reached up to the cockpit roof, pulled the air brake lever and committed to the landing.
It did a gentle left turn back to the airfield and came down to a lower height". Mr Hannant said the plane made a gentle descent to 1,400ft (425m) adding that the crash happened 11 minutes after take-off at 11 17.
But a continuous gentle descent to the airport would be more fuel-efficient.
Emin is approaching 50 and she is worried about the possibility of a lonely, gentle descent to death.
With The Revenant certain to remain very much part of the awards conversation through to the Baftas on 14 February and the Oscars on 28 February 28, box-office is likely to continue a relatively gentle descent.
The road narrows to two lanes as the combined highways begin a slow, gentle descent through less developed areas to the bridge over the Wallkill River, situated at the northern tip of the county's Black Dirt Region.
From Merlet it was a long but gentle descent back to Chamonix, with more fine views across the valley.
