Ab Initio 48: “Under the Hood”

In which I fly around for an hour without seeing sky or ground and discover why “Thou shalt not fly into cloud” is a really very good idea.

The weather wasn’t good enough to go anywhere today, athough the cloudbase and wind were fine. The visibility was atrocious, so Plan B was to do some instrument flying.

There was a half hour trial lesson going off before me and the aeroplane had decided to put up a fight while Laurie did the walkaround checks. This resulted in me being dispatched with a pair of pliers to tackle a stuck oil filler cap, while he briefed the trial flighter.  The look on their face upon asking “Oh do you work here?” and getting back, “Oh now I’m a student” was a picture!

Once they returned I scooped up the instrument flying ‘hood’ from the table, not the most elegant item of apparel but does the job of blocking your view of everything but the instruments, and we headed out.

The plan was to take off, intercept the 275 radial from the Brecon VOR and track that for a while.

275 FROM is the same as 095 TO so as our heading to Brecon would more or less easterly it would be easier if we used the TO indication. I therefore set 095 at the top of the OBI dial.

A puzzled few moments later while I tried to figure out why it was already showing centred when I knew we weren’t anywhere near it, ended when Laurie pointed out the NAV flag showing.

“What does that mean?”

“Ermm. It’s not working.”

“All right. Why is it not working?”

Quick cast about. Sudden enlightenment. “It’s not switched on?”

It does help if you switch these things on when you want to use them! I did so, and the needle jumped off to the left. This made now made sense with what we knew about where we were and the track we wanted.

Laurie fished in the back for the hood and took control while I wedged it on my head.

All I need to do now was keep on this heading until the needle centred. Being able to keep the wings level would aid this no end–but once again the moment I couldn’t see out I was wobbling all over the place.

Slowly the needle drew closer to the centre of the dial, and when it was almost there I started a very cautious turn onto 090, allowing the extra five degrees for the northerly wind.

We levelled out at 4000′. Well we intended to. It was a very untidy process. I’m sure I knew how to stop a climb last time I flew, why has my brain suddenly turned to mush? We eventually settled for 4300′ once I finally got properly trimmed.

By this time the needle was off to the left again and we turned back onto track. This went on for some time as I wandered from one side to the other having abruptly lost any ability I might have once had to hold at least an approximate heading!

This wandering did get less pronounced as the lesson went on, as I got the a bit more used to keeping the wings level just by reference to the AI, and got into the habit of checking the DI more frequently than I was used to.

We’d come quite far east by now so changed to Swansea to let them know we were about. We also got a QDR from them to plot against the radial position line to fix our position. Somewhere over Llanelli apparently, though I’d lost all sense of where we were by now other than “somewhere east of Pembrey”!

Next up was an about-face and track the same radial back again. This was to be a ‘rate 1’ turn so would take a minute to turn through 180 degrees. It seemed more like six months! The longest minute I think I’ve ever experienced. And that was on a nice smooth day, when feeling relatively relaxed. I can well imagine it must seem longer still if you were doing it for real as the “turn tail and get the hell out of cloud!” manoeuvre it’s taught as.

We managed to pick up the radial again a bit quicker this time and I was reasonable at tracking it rather more accurately this time. We changed to the Strumble VOR to practice getting a position fix using two VORs, although it was quite a ‘loose’ one as it was a rather oblique cut. We stayed tuned to Strumble and tracked towards that for a while before doing another interminable 180 and heading back again.

It took a little while to establish the correct heading to allow for the wind here. The difficulty was soon revealed as being caused by a drifted DI which no longer matched the compass!

This time we were going to track the radial which went straight from Strumble to Pembrey and see if we could work out when we had arrived by using a radial from Brecon which also went through Pembrey. When we crossed that one, the needle should centre and give us our position fix.

Again this works a bit better when your two VORs are conveniently placed so you can get a good angle between them and you but it worked well enough to demonstrate how it was supposed to be done.

As we rejoined at Pembrey, Laurie called out headings and heights for me to fly as we started to descend. I let the descent get away from me a bit at one stage, and I slipped out of the flap limiting speed for a moment after I had lowered them. No harm done fortunately, but I did slow down a fair bit after that!

The hood came off shortly after turning final and it was almost odd to suddenly see the ground again.

Not the tidiest of landings either, but an interestingly different hour.

We went over some of the details on the ground. Things mentioned in particular include the differences when flying in real IMC, when the subconscious clues you get which you get even when under the hood from things like shadows from the sun through the windows, are not present. Also, the temptation to fixate on the DI when turning, instead of monitoring the bank angle on the AI, which I had definitely noticed myself doing. As we’d been practising, timing the turns and just glancing back occasionally to see how it’s progressing, helps avoid that.

Interesting stuff. Though I’m not sure that it makes the prospect of accidentally ending up in cloud less alarming or more so!

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