The phrase "allow clearance" is correct and usable in written English.
It can be used in contexts where permission or space is being granted for something to pass through or be unobstructed.
Example: "Please ensure that all equipment is moved to allow clearance for the new installation."
Alternatives: "permit passage" or "grant space".
Bloggers have speculated that the big double garage doors will allow clearance for Mr. Palin's Piper Cub airplane and maybe his snowmobiles.
Disneyland Drive, which had separated the two theme parks at street level, was lowered by 15 feet, while the level of Disney Downtown was raised five feet, to allow clearance for cars and trucks driving beneath the pedestrian bridge.
BACKGROUND: The aim of this study was to assess the feasibility of delivering NO through a modified system to allow clearance of the magnetic field and thus compatibility with cardiac magnetic resonance (CMR).
Endocytic activity is significantly higher in bloodstream forms where it may also have a defensive role in recycling of the variant surface glycoprotein (VSG) to allow clearance of surface bound antibodies [1], [2].
Manufacturers of dialysers would provide sufficient data to allow clearance of key toxins to be predicted.
Two HPV tests 8 to 12 months apart are sufficient to allow clearance of infection.
The body of evidence, which suggests that protective immunity allows clearance of hepatitis C virus without seroconversion is growing.
The gap between the tack strip and the baseboard allows clearance to tuck the edges of carpet down and hide any irregularities.
A gap between the panels and the internal edges of the groove allows clearance to accommodate the panels as they expand.
"The fear appears to be that detainees will try to smuggle coded messages out of the camp," explains Falkoff, a fear that has often allowed clearance for English translations only - Arabic or Pashto originals being judged to represent an "enhanced security risk".
In Gilchrist v. Collector of Charleston (1808), Johnson, while holding federal circuit court, allowed clearance from the port of Charleston to a ship detained under Jefferson's Embargo Act of 1807, a measure intended to preserve U.S. neutrality in the Napoleonic Wars.
