Flying at 170m, why we needed a Drone TRA?

Why did we need an IAA TRA to complete a commercial job?

In June of 2022, Drone Services Ireland was engaged by an International Client to perform an Aerial Survey of an Irish Cement site. Located at Platin, on the outskirts of Drogheda, it was well known to us. We had specific requirements to meet in terms of resolution and accuracy from the client.

As the chimney stacks are visible for many miles in the area, we decided we needed to conduct an on-site recce. The on-site survey is good practice as we knew the chimneys and cooler stacks were tall. Only when we flew the drone up the full height of the stack did we realise they topped out at 120m.

At this point, we knew we needed a different approach. Under our EASA Specific Category Operational Authorisation, we are permitted to fly above the tower but need to be within 50m of it. We engaged with the UAS Manager within the IAA and we set about applying for a TRA. We needed to fly over the whole site at a constant altitude to maintain the ground sampling distance required. A smaller Mavic or Phantom drone was not going to cut it. 

Working with the IAA, we applied for permission to fly at 170m AGL within 1 nautical mile of the plant, and Drone Services Ireland was granted the required authorisation. The airspace was closed off for the time of the survey. TRAs and NOTAMs, notify manned and unmanned operators of the exceptional conditions for the drone survey and these were published by the IAA on their website and through social media channels.

The DJI M300 RTK with P1 was flown at 170m with flight termination system and parachute on-board. The 45MP images from the camera providing less than 2cm ground sampling distance (GSD), which was more than enough to meet the needs of the survey. Resulting in a pleased client and end-user, while demonstrating our ability to complete this work safely and efficiently, the safe approach, in this case, proved its worth.