What a drone survey entails
It may appear to some clients as though we turn up, get out a remote control toy (sometimes a large toy), fly around a bit, and give them a memory stick, all in about an hour. But of course there’s a lot more done behind the scenes.
What you get for your money
These are the procedures we go through
- On receipt of an enquiry we firstly look at the planned location on a navigational chart, or use an app such as Sky Demon to confirm what type of airspace is above the potential site. A great deal of UK airspace has restrictions in place. So long as it is not within a “no fly zone” we confirm the feasibility of the flight and submit a quote.
- On acceptance of the quote we then carry out a risk assessment using Street View, Google Earth and some specialist apps. We measure the exact location from hazards such as mobile masts, public spaces, railways, power stations, prisons, etc., in addition to airports, helipads, glider clubs and other potential dangers.
- When we are within an airport’s exclusion or caution zone we contact air traffic control to see if we can get permission to fly without having to request special permission from the CAA (which takes up to 28 days and permission can be withheld without any reason stated and no return of fees).
- We also check Notice To Airmen, or NOTAMS, controlled by NATS, for any temporary restrictions in the airspace.
- Dependent on the planned time scale. we also check the weather with the Met Office, and a back-up weather source for suitability of the conditions on the proposed date.
- We then fill in our pre-flight survey documentation.
- We select 2 drones for the job, usually one small and one large. This is to allow for what is actually required, as quite often once on site we discover a reason for close up work. Rather than zoom in with the camera from 50 metres we send up the small drone to get in close and tight.
- The day before the planned flight, the drones are physically checked and spare propellers, etc., are packed. The batteries are then charged to 100% and the process is recorded in our flight record books (each battery is separately accounted for and we carry 7 or 8 for every job as a minimum).
Only then are we able to fly.
- On the flight day itself, we load the vehicle and drive to the site.
- Once on site we carry out a further risk assessment and have a quick briefing with the client regarding safety and the exact requirements and expectation of the survey. When required, we also notify interested parties such as the police or a local council by phone from the site.
- Once all drones are assembled and all pre-flight checks complete we take off — always keeping a clear line of sight with the drone.
- We post a NOTAM to warn any other aircraft exactly where we are flying, how high and how long for from site via the NATS app. We also use the same app to make sure that no NOTAMS have been created temporarily restricting flights between our planning and the flight day.
- To get the requested data, we then fly. This can be for as little as 20 minutes in the air, but most are around 45 minutes’ flying time.
- Once landed. we transfer the photos/data to a laptop to ensure that all is correctly recorded. We also check with the client to ensure that there’s nothing more that they need to see while we’re on site.
- Then we pack up and leave.
- Once back in the office, we check the quality of the imagery and copy to a memory stick which we post, Royal Mail signed for, to the client.
You can see the time on site is actually a relatively small part of the survey.