The helicopter owned by South Yorkshire Police has been grounded for six months because of delays in its annual maintenance check.
The machine has been out of action since January as the process - which regularly takes a minimum of six weeks – has been set back by technical problems.
One of the helicopter’s two logbooks has also gone missing although police say this is not the reason the aircraft has been grounded.
In April the helicopter transferred to the National Police Air Service - which is currently loaning a cover helicopter during peak times to South Yorkshire Police with out-of- hours cover from other nearby forces.
The original helicopter is currently in Gloucestershire, awaiting parts from America.
Superintendant Simon Verrall said: “Each year the helicopter is required to go through an extensive annual maintenance process which we entered into in January and, for various technical reasons, we were unable to complete that process before the transition of the helicopter to NPAS in April.
“The process can take quite a while and its not uncommon for helicopters to be grounded for significant amounts of time.
“The service means the helicopter is taken apart and put back together again.
“There are a number of unworthy air faults on the helicopter, things like one of the rotar blades is damaged.
“These parts are difficult to locate and expensive when they are found.
“We often have to send them part to the manufacturer McDonnell Douglas in America.
“If the parts are not replaceable they might have to be made.
“It’s not like taking your car in for a new gearbox.
“The helicopter has two logbooks, an engine one and an airframe one, and it is the airframe one that is missing.
“That is not stopping the aircraft from flying.
“We are in the process of reconstructing that record so that the Civil Aviation Authority will be satisfied that the aircraft will be fit to fly.”
Supt Verrall could not say when the helicopter would return to service but confirmed it would take three or four weeks once all the parts were available.
He also said the helicopter’s grounding had not cost the force any extra money.
The local bill paid for the national service every year is £1.7 million.