Caernarfon IFR

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Low Cloud but warm and (not too) windy

Low cloudbase of 900 feet (broken 600) at Gloucester meant there was very little activity. It was forecast to clear during the afternoon, and the weather looked better to the west, so I picked on Caernarfon as a destination for a day trip in the TB20. Dave, who I’ve flown with at Lyneham came along for the ride.

This was very much an IFR departure, with a procedural service (i.e. no official radar, ATC provide separation only by pilot reports). At ATC’s suggestion, we departed from runway 27 rather than 22, since there was only 3 or 4 knots of wind. We were soon in the soup then quickly above the thin cloud layer and into the sunshine. I cruised at 4000 feet, talking to London Information who seemed to be pretty quiet. Unprompted, they provided updated weather for near to our destination, reporting cloudbase with few at 1100 feet and scattered at 1700 feet.



Scattered Cloud in Wales
Broken cloud over Wales
Clear front in the cloud

Caernarfon is on the coast and so its quite feasible to descend (in cloud) above the sea and approach at circuit height. As we proceeded west, there were more obvious breaks in the cloud giving good views. We saw a clear path out to see via Barmouth should we have wanted to go that way, but instead pressed on over the mountains and descended VMC into the overhead.

Strong crosswind

Caernarfon has two runway and with a wind of 180 at 20 knots, Runway 20 would have been preferable. However there are two wind turbines right next the runway and it isn’t used when the wind is less than 200 degrees due to wake turbulence. So we’d be on runway 25 and get the full effects of the crosswind.

I had let Dave fly much of the leg manually but took over as we descended into the circuit. There was no other traffic to worry about. I had the CDI aligned with our target runway using the OBS function of our GTN650 which helps a lot to ensure you are setup for the right one. The large rudder on the TB20 copes well with these stronger crosswinds – it’s rated up to 25 knots demonstrated crosswind.

Horizontal Windsock = 20 knots

Spruced up

I barely recognised the airport buildings which have all been radically improved since my last visit. The old crumbling tower building is no more, and instead a swanky modern new one has been erected. Nice hangars with horizontally bi-folding doors are home to the commercial SAR helicopter and other users. The cafe has had a refresh and looks more open and bright. It was quite busy with visitors and we only just got a table to ourselves.

Autopilot, GTN and a (practice) distress call

We flew the return leg on autopilot and worked through the GTN features, loading up the next frequencies from its database and exploring how it even knew which airports have pilot controlled lighting. We also made a practice pan to D&D in Swanwick. It’s nice to know they can pin-point you anywhere in the UK in just a few seconds. We were a few miles east of Llanbedr and I thought they’d give us our bearing from there, but instead they noted we were 10 miles south of Portmeiron which was spot on.

Someone else came on frequency also wanting to make a practice-pan, but for some reason didn’t listen out first and trampled on the last part of our exchange. I hope they wouldn’t do that if there was a real emergency in progress.

Patchy cloud banks
Crossing back
Crossing back towards the coast after climbing up through cloud layer

RNAV 27 into Gloucester

I demonstrated the RNAV approach back into Gloucester on autopilot and everything went like clockwork. There was definitely some sink shown on the VSI as we passed over the ridge which wasn’t reflected immediately on the altimeter. I think that has caught me out in the past and I shouldn’t let myself be too concerned about sudden changes in the VSI during an otherwise stable approach.

This was Dave’s first experience of a “real” RNAV IFR approach in cloud and he said the sequence seemed quite straightforward to him. Although there was no delay for our approach clearance we were held high (in VMC above cloud) while Gloucester warned of a departing aircraft climbing out at a similar range, direction and altitude to us. Once deconflicted and the other aircraft had accepted a Basic service, we could descend through the cloud while complying with procedural service separation.

I’d estimate that we popped out of cloud at around 1,000 feet QNH (so 900 AGL) and I called out the RNAV minima (600) and ILS (200) to illustrate the difference. I commented that what we had flown today was quite achievable with the IR(R) rating which Dave seems quite enthusiastic to work towards in the near future.

PIC Today: 2:20
Total PIC: 446:10
Total Time: 593:40

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