Lesson 30: IMC, Dual land-away to Shobdon and an SRA approach to Gloucester

I had the entire afternoon booked out today, so we could get lots of flying done.

I needed to practice flight in IMC (not because I’d be allowed to fly IMC with my initial licence, but as training incase one inadvertantly enters IMC and needs to get out..fast). IMC is short for Instrument Meteorological Conditions and is basically when you do not have sufficient visibility to fly visually, such as flying in cloud, fog or strong haze.

After doing some IMC practice, me and my instructor  would fly to Shobdon together, have a quick bite to eat, fly back to Gloucester and land using a Surviellance Radar Approach (SRA). Then I’d go fly the route solo. Or at least, that was the plan…

In the pre-flight briefing, we talked about the the ‘six pack’ instruments – the basic six instruments in pretty much every plane. They’re arranged in two rows of three, so three on the top row and three on the bottom. Can you name each one? I managed 5 out of 6 and got stuck trying to think of the last one. It’s much harder than it sounds!

The aircraft six-pack
The basic six-pack

When flying in IMC, it’s essential that you scan the instruments according to a defined order. The main instruments are in a T shape (airspeed indicator, artificial horizon, altimeter on the top row, followed by the direction indicator on the bottom).

Even flying straight and level (which is pretty easy in VMC) is very demanding when flying in IMC. This is because you need to scan the T every second. Yes, every one second. Are we flying straight? Lets check the DI. Check the AI. Check the DI again. Still the same? Yes. Good, straight. Are we flying level? Check the altimeter. Check the AI. Check the altimeter. Still the same? Yes. Good, level. Every time you look at an instrument that isn’t the AI, you should immediately look at the AI next.

You can see how the workload ramps up very quickly in IMC. Doing a FREDA check whilst incorporating your T scan suddenly makes things much more difficult. Add in a radio call and you can see how things can go wrong very quickly if you’re not well prepared.

When turning in IMC, turns are normally conducted as a rate one turn. A rate one turn means that it takes one minute for the aircraft to turn 180 degrees. It therefore follows that turning a full 360 degrees (an orbit) will take two minutes.  The turn co-ordinator (bottom left in the six pack) has markings on the left and right which –  when aligned with the aircraft wing – means you are doing a rate one turn.

If you inadvertently enter IMC, the first thing to do is check the MSA for your current position. If you’re below it, climb pretty quickly. Clearly as a basic PPL, you’re not qualified to be in IMC anyway so if you do fly in to a cloud then you should do a rate one turn for one minute (eg 180 degrees) to head back out of the cloud.

Finally in our pre-brief we talked about the SRA. Whilst not part of the PPL syllabus, my instructor suggested we do one anyway as it’s good experience. Whilst flying IMC there are various methods available to approach and land at an airfield. The exact methods available will depend on the airfield and your licence, but could include an NDB approach, ILS approach, radar vectored approach, etc.   An SRA is one of the simpler approaches and is likely to be used if you do inadvertently enter IMC and need help from ATC to get down. Essentially, the tower uses radar to identify your position and then issues instructions for you to change heading to align yourself for the approach. Each SRA has defined minimums and the one we’d be flying would take us to 2nm from the runway threshold. Some go down to 500metres (or less).

We headed out to the aircraft and did the usual pre-flight checks.  We were soon up in the air and my instructor put up the instrument screens. These basically block the pilot’s view – I couldn’t see out the windscreen or the left window, effectively simulating IMC conditions. The instructor’s view is unobstructed so he acts as safety pilot maintaining good lookout during the training.

I practiced flying straight and level, through reference of the instruments. It’s certainly more involved than it sounds, but after a while I got the hang of it. Felt a bit like using a flight sim as you’re fixed on the instruments. We then did some rate one turns, which seemed fairly straight forward – make sure the turn indicator is on the right notch and make sure you are flying level and everything’s cool.

After a bit more flying with the screens up, they came down and I headed towards the approach for Shobdon airfield. Shobdon has a non-standard join procedure, which involves descending not below 1500ft on the deadside, and then descending to circuit-height (1000ft) on the live side, to join the circuit mid-way downwind. I got a little confused at first but soon got myself sorted out and everything went well. We landed, taxied to the grass parking area (remembering to change between surfaces at 45degrees) and headed to the cafe and paying the landing fee.

A while later, we booked out and prepared for departure. We were soon up and away, and heading back towards Gloucester. Up went the IMC screens again and I did some more rate one turns, climbing, descending and straight and level. The instructor spoke with ATC and requested an SRA for runway 09 which was accepted. Firstly, they needed to identify our plane on their radar. (Gloucester don’t have secondary surveilance radar, which interrogates the transponder and enables you to use a unique sqwawk) so to identify you they ask you to turn a specific heading. We obliged and a few seconds later, they told us we had been identified. We were then given a series of instructions “turn right heading 170” and information “you are 9 miles from the threshold at 2000ft” and as we followed their instructions our track was nicely aligned for a long final approach. At 2nm the instructor took down the screens, the SRA service was terminated, and – sure enough – I was staring at the runway straight ahead – magic!

Annoyingly my GoPro memory card filled up before we did the SRA, otherwise I would have uploaded the video as it was quite a cool experience. I’ll try and do another one and upload it in the future.

We landed and had a coffee and a re-cap. Unfortunately, as is common with most of my lessons (we like to talk!), things had overrun a bit and it was too late for me to fly the route solo that afternoon as Shobdon would be closed. Nevermind,  I’d fly it solo next time…


Leave a Reply

Your email address will not be published. Required fields are marked *