Hour 2
My apologies for those who may feel that this diary does not have the frequency of updates that other diaries enjoy. Like many who amble along in the private flying forum (I suspect anyway), I can only generally get airbourne once a week or so.
Instrument flying is quite clearly a practised art, a fact becoming ever so evident to me this afternoon. I was going to be developing my skills from merely being able to fly on instruments to actually using them to navigate. Hence the addition to my instruments to scan of the OBI (Omnidirectional Bearing Indicator). Basically this fine instrument tells you whether you are left or right of a desired track to or from a selected VOR beacon. As it is quite a complicated instrument to explain, it is best left to my new found bedtime reading material "The Air Pilot's Manual - Volume 5", suffice to say initially it caused me a couple of minor upsets.
I arrived at the airfield full of anticipation today as unlike my previous flight, there were actually some clouds about and I might actually get some proper un-hooded IFR flight time. My instructor was still airbourne in a different aircraft so I took the opportunity of uncovering and pre-flighting the aircraft. Once completed, I settled in to a nice cup of coffee and 15 minutes later we started briefing. We covered where we were going to operate (Daventry VOR), the route out and the exercises we were going to fly. Never one to miss an opportunity, I reaffirmed my read up homework and we discussed the OBI and how to use it. This included the set up proceedure TITO.
T Tune in the required beacon.
I Identify the beacon.
T Test the beacon/instrument.
O Orientate the Instrument.
My aircraft has a combined GPS (only ever used for remaining clear of controlled airspace!), Comms radio and Nav radio set up. So I have quite a complex piece of kit to learn on but all becomes more relevant later.
We walked out to the aircraft, started up as usual and off we went. I took the chance during the startup to set the Nav radios, but due to the fact we were on the ground and were not within a line of sight of the beacon, it obviously gave no indication. Once airbourne and departing to the Southeast the OBI came alive and I set 130 on the OBI which was the QDM towards the Daventry beacon from our location before turning towards a heading of 130. I was given the grace of being allowed to identify the beacon and test it before the dreaded hood. Each beacon transmits a morse code 3 letter identifier along with it's navigational signal and by turning the Nav audio on, you can listen to this morse signal and identify you have the correct beacon. Sure enough Delta Tango Yankee came over my headset and I then tested the instrument. I simply did this by cahnging the frequency of the nav radio, watching the OBI needle go to the side and the warning flag come up. This told me that the intrument was not recieving any signals from a VOR and on restoring DTY, the needle came back and the flag vanished telling me I had a nav signal. I had already orientated it to 130 so all of my checks were complete and on went the hood.
Cool, now I had an 8th instrument to play with. I had my 6 flight instruments, my tachometer and now the OBI. I was mesmerised by the needle, following it's slow but deliberate movement away from the centre. I was going off track so skillfully, I used my AI to enter a right turn and my DI to set the heading of 140. Hey how hard can this be. But wait, why am I 200 feet too low, no problems, back to the AI, raise the nose a touch and bing.....ohh why am I flying 120 degrees, I want 140. No problemo, slight turn to the right and whadya know I'm too high and still off track. Why won't it turn right to 140? Like a muppet, I had a new toy and had stopped my scan, missing the fact I was flying out of trim and spending too long looking away from my AI.
A thorough self administered beating later, I had forced myself to revert to a proper scan. There are 2 types of basic scan, a radial scan used if you are on autopilot or such like where all you are looking for is inconsistancies in instrument indications to alert you of problems and what I would call a "spoke" scan. Imagine the AI is the hub of a bicycle wheel and with this it becomes your primary focus. From this point spokes radiate out to each of the other required instruments. Most of your attention is focused on the AI as it is your attitude information and hence with your power setting determines the aircraft's performance. From the AI you glance to single instruments before going back to the AI. For example to maintain straight and level you may go from your AI to your DI to check your heading, back to your AI to ensure you are maintaining attitude, then to your altimeter to check your altitude and again back to your AI. Every now and again you can then insert a check of your ASI or slip ball to check balance etc.
Now I had the thing in control again, we tracked all the way to DTY and as planned flew through the overhaed to examine what happens. To cut a long story short, VOR beacons don't transmit a signal directly above and so as you close, the OBI becomes very sensitive and then goes off to one side showing no signal before coming back to life on the far side. As it does so, the to flag changes to from to tell you that the set OBI heading is going to take you away from the beacon. We continued for 3 to 4 miles before doing a rate 1 turn to the right. The intention ws to set up an intercept of the 360 track to DTY but with my turn and the wind, we ended up pretty much overhead the neacon. With 360 set on the OBI I flew 330 waiting for the needle to move in from the left. Not a flicker. We should have neen well away from the overhead, why wasn't the needle moving? I turned further left to 320. Still nothing. Putting me out of my misery my instructor pointed out that the magnetic compass was showing a heading of 350 to that of my DI which had drifted well away. DI brought back to 350, a turn to the left and bingo, the needle on the OBI , moved, I was getting back on track. I'm concentrating on the instruments that much, I am scaring myself with the fact I have lost a lot of my basic airmanship skills. My hope is that as I become more attuned to my new environment, I will have more mental capacity to bring them back in, but then hey, last week I couldn't fly a specified track on a VOR. Now I can. We went North and then turned 180 degrees and practices an intercept of the 180 QDM (heading towards a beacon as opposed to QDR which is a radial from a beacon).
After a bit more VOR tracking we headed back to the field where we set up for a straight in approach. This gave me the chance to try my first ILS approach. Put simply it is just a much more sensitive VOR which gives glideslop information. Working to IMC limitations, my decision height would be 800' on the QNH (the decision height is based on a number of factors but IMC limitations are more restrictive than those applied to an Instrument rated pilot). The concentration was intense, but I managed to nail the track at 2000 feet altitude and as the aircraft drifted right of my chosen track of 230, I went to 220. This brought the needle back into the middle and I then bisected the 2 headings hoping 225 would be a good wind adjusted heading to track me down the centrline. All was looking good until I ganced at the glideslope indicator which was racing past the middle of my instrument. Damn, I haven't even started a descent yet. Carb heat hot, power to 1900 and stuff the nose down 5 degrees. Phew it's coming back. I'm quite a modest person usually, but nailed the approach. Although I was sweating and couldn't talk, I nailed it. 800 feet, hood up and there she was in all her daylight bathed tarmac glory, runway 23. Another hour airbourne, 50 minutes instrument time logged amd lesson over.
Todays lesson in summary, if you can't or even won't scan properly........
Stick to VFR. For me anyway this needs serious practice and I would say that with 75 hours experience it is readily achievable, but far more demanding in terms of piloting skills than the PPL.
Have a nice week, I hope to be flying in the middle of the week - A VOR and NDB based nav route.
Obs cop
PS. I only know of 30 seconds of actual IFR in the clouds! Today I was mainly hooded again.
