Why do police helicopters always fly in circles while news helicopter hover in one spot? Is it to avoid criminals opening fire at them, or is it because there is a difference between the two types of helicopters?
Police helicopters don't always fly in circles. I've often seen my local police helicopter hovering. There are a few reasons you might have seen police helicopters flying in circles:-
- Not all types of helicopter can hover out of ground effect. It might be that the police helicopters in your area can't hover at the heights they work at, with the weight of their usual equipment.
- Helicopters are safer if they're moving forwards than hovering. In the event of an engine failure, they can autorotate to land safely, but they need to have some airspeed to be able to do this. The required airspeed depends on height (see the chart in the linked question), so if your news helicopters are usually operated higher up than police helicopters, they may be able to hover safely. (This is quite likely, as police aircraft are exempt from the 500 ft rule and the 1000 ft rule, while news helicopters are not.)
- Police helicopters often circle to search an area for a fugitive or casualty using thermal imaging cameras. News helicopters tend to either follow a vehicle or hover to get a steady camera shot of a news event.
There is little difference between the helicopters used by news crews and police. It is their operation that differs.
Flying instead of hovering helps minimize the chance of getting shot. There has been incidents when law enforcement helicopters have been shot down.
Forward flight (at low speed) uses less power compared to hover. This reduces the engine load and increases the time spent over target.
Police helicopters fly pretty low compared to the news helicopters. Hovering for long periods can result in one settling in their own downwash. In this case, the altitude can help news helicopters to gain forward momentum to get out of this. As this option is not available to police helicopters, it is better for them to fly in circles.