Archive for September, 2007

First nav!

Sunday, September 16th, 2007

Time flown today: 1h 15m

Total time so far: 26h 45m

For the first time, I was flying first thing in the morning, since the late evening slots are no longer possible. It started with a lengthy brief on the principles of navigation, and the plan for the day. All fairly straightforward, though:

  • Depart runway 19, follow the railway to Charlbury, then route Charlbury-Evesham-Banbury-Kidlington, for an overhead join to land.
  • Circle the waypoints on the map, and draw the connecting lines.
  • Note the minimum safe altitudes - more than 1300ft above the highest point within 5nm of the track, or above 500ft (i.e. 1800ft) if nothing is marked.
  • Get the met, and do the plog calculations to obtain magnetic headings and leg durations.
  • Mark half-way points for each leg on the map. These are good for ETA progress checks, and FREDA cruise checks.

So we went to the aircraft, did the usual start checks, and prepared to set off. Ground, Tower and Approach were all active on different frequencies at this time of day, so the taxi call was to Oxford Ground. At the runway holding point, we made the simple call to ground:

“Golf Bravo Tango Golf Oscar, over to Tower”.

One significant flaw in my radio calls thoughout the flight, is that I used the abbreviated callsign in responses before ATC did, because I wasn’t properly listening for it. I need to make a point of listening carefully and getting this right. Anyway, I changed to Tower, and announced:

“Oxford Tower, Golf Bravo Tango Golf Oscar, ready for departure”.

I also requested a right turn, and when Tower queried this shortly after takeoff I think I mis-understood something and repeated that we’d requested a right turn. The instructor intervened, but I still don’t understand exactly what happened. Anyway, shortly before reaching the railway south of the airport, we turned westwards to follow it. The instructor said that it’s important to stay north, to avoid entering Brize Zone. At that point (about three miles west of the 01/19 centreline), the railway is actually a good distance north of Brize Zone (the edge of which is about a mile north of Eynsham parallel with the A40), but I wasn’t going to argue. We followed the railway north, past Woodstock, Long Hanborough, Stonesfield, and soon enough Charlbury appeared ahead. Meanwhile, time to change to Oxford Approach:

“Golf Golf Oscar, to Approach.”

(Tower acknowledges)

“Oxford Approach, Golf Bravo Tango Golf Oscar is airborne to the west, request Flight Information Service.”

(Approach acknowledges)

“Flight Information Service, Golf Bravo Tango Golf Oscar.”

I think I probably erroneously used the abbreviated callsign in response, when Approach used the full one. I need to stop doing that.

So with overhead Charlbury, I noted the actual time of arrival (ATA) of 45 past the hour, planned the ETA for the next waypoint of Evesham (58 past the hour), did a FREDA check, and the instructor took control to let me get used to this mapreading and visual navigation business. I suppose it helps that I know the area pretty well, both from the ground and from road maps, and that the conditions were perfect. But even so, it was all pretty easy, fixing our position from the combinations of villages, roads, railways, high ground (which is distinctive and useful in the Cotswolds), and disused airfields. The leg half-way point of Moreton-in-Marsh appeared on the nose exactly as expected, and as we approached the instructor declared that it was all too easy for me, and gave me control. Did the FREDA checks as we passed just south of Moreton, and settled down to resume the pattern of reading the ground and the map. I noted that the instructor was fiddling with the VOR: he’d set it to 116.4 for Daventry, and found that we were roughly on the 240 From radial as we passed Moreton. I’d been unconsciously applying a little back-pressure on the yoke though, and we’d climbed 100ft above our desired altitude: it took me nearly until the Cotswold escarpment to sort that out, because I didn’t correct it positively enough. But apart from that, everything went completely to plan, Evesham appearing on the nose exactly as predicted, bang-on ETA. The instructor made a fair effort to distract me, but checking heading and altitude every ten seconds or so is an easy habit to get into regardless of what other conversation or navigation I was engaged in.

At Evesham, time to follow the waymark routine - turn, time, talk and task:

Turn: the course change was about 150 degrees, so a teardrop turn in the opposite direction was executed to bring us onto the new heading over the centre of the town. This gave a good opportunity to thoroughly eyeball the town, and get numerous positive confirmations of its identity: the distinctive bend of the river in the town centre, the railway heading out to the north-west, the dual-carriageway out to the north, and Bredon Hill about four miles to the south-west.

Time: as we emerged onto the heading for Banbury, 23 miles distant, at exactly the hour, I noted the ETA as 14 minutes past.

Talk: not really necessary to talk to anyone this time.

Task: a FREDA check, then back to maintaining the course.

Navigation towards Banbury continued. It was thoroughly pleasant, not only looking at the pretty view but actively studying the ground features to establish and confirm where we were. The instructor plotted that Banbury lay on the 235 radial from the Daventry VOR, so he set up the VOR to indicate when we reached the end of this leg. I’d failed to notice that our course clipped the edge of a gliding site, though: for some reason, the blue G in a thin circle evaded my brain as I stared at the course on the map. The instructor suggested that we should detour to the south of a village just south of the gliding site, to make sure we avoided it. After we passed the leg half-way point of Shipston-on-Stour, I began scanning the horizon ahead for the site: but it came up much quicker than I expected, and I failed to see it. I should have realised that being only about five miles beyond Shipston, we’d reach it in less than three minutes. Anyway, by the time the instructor finally pointed my eyes in the right direction, we were about to infringe it and we had to take quick action to keep clear. On clearing it, we were visual with Banbury from our slightly diverted position, so I flew directly there, the VOR needle nudging towards the centre as we approached the town.

Time for the last leg! Set a course southwards from the middle of Banbury, and continued the navigation. We saw some glints in the haze, possibly at a similar level - fearing conflicting traffic, we turned the landing light on and kept a keen lookout, but nothing else materialised. It may have been circuit traffic over the airfield, or possibly even in Brize Zone. Anyway, we had the DME tuned to Oxford, and at 5 miles, with the airfield just visible, we made a call to Oxford Approach, addressing them as if it was a first call since we hadn’t spoken to them for over half an hour:

“Oxford Approach, Golf Bravo Tango Golf Oscar, airfield in sight, request standard overhead join.”

The overhead join was approved, and we were instructed to report overhead. I can’t recall exactly how and when we changed to Oxford Tower, but soon enough we found ourselves approaching the airfield, so I descended to 2300ft for the overhead join. We’d been hearing a slightly-confused microlight heading towards the airfield, requesting a transit through the overhead at 2400ft, and ATC were a bit concerned that we’d conflict with them. Our entry to the overhead join was a bit delayed, because I set off around the wrong way around the airfield and had to do a 180 to get to the right point to start the join. But never mind. I got into the correct position, answered ATC’s rather anxious enquiries about our position and height with respect to the approaching microlight, and quickly started descending round the dead side. The overhead join was pretty good, although once downwind things were a little ropey: altitude control slightly wayward and the turn to base a bit uncoordinated, but I held it together well to make a great approach and landing, with a length hold-off and gentle touch-down. 8/10.

I should check what the points are for changes of radio service, and what the calls are. I should also check my route more carefully for things like gliding sites that might get in the way!

Sheep worrying

Wednesday, September 5th, 2007

Hours flown today: 0h 40m

Total hours to date: 25h 30m

Today, I had the last evening lesson of the summer. The instructor professed to be knackered, and so the lesson turned out to be rather shorter than expected. Still, he had the good grace to comment that he wondered if he’d wasted my time, as we taxyed back in afterwards! The lesson felt easy, but actually I made a number of noteworthy mistakes along the way.

First mistake was not tuning the radio before transmitting to request taxy! It was still set to Tower, and now Tower and Approach were combined on the usual Approach frequency. We taxyed out and took off on 01, shortly making a left turn to the north-west and levelling out at 1000ft QNH: only about 700ft AGL. The first part of the lesson was flying at low level. It needs an alert lookout and attention to speed and altitude, but is otherwise easy - and fun! Very satisfying. We flew towards Charlbury - my superior knowledge of the local area actually trumped the instructor, as he was “uncertain of position” due to the dazzling low sun, while I recognised the A44 beneath us, just south-east of Enstone village. Intercepting the railway in the valley north of Charlbury, we descended to 800ft QNH, the limit of the 500ft low-flying rule since the ground is about 300ft AMSL there, and tracked the railway up the valley. It was relaxed and thoroughly pleasant, meandering low over the countryside. Points to remember about minimum-level flying:

  • Keep aware of changes in the ground elevation, so you don’t inadvertently bust the 500ft rule, and ultimately so you don’t crash into hills.
  • Remember that visual range to landmarks will be much more limited than at 2000ft, so visual navigation is difficult without a line feature.
  • Watch out for radio masts, which are sometimes more than 500ft high and could really spoil your day, and high-voltage electricity lines.

Next, we practiced a forced landing with power. This might be used if a descending cloudbase forced a landing, for example. We climbed to 1000ft AGL, and I identified a suitable field close-by. The aim is to fly a conventional (if extremely compact) circuit pattern around it, descending to 500ft AGL crosswind to thoroughly inspect the field. Close inspection from crosswind revealed no animals but two sets of fences intruding into it, but a clear gap in-between of 40-50 metres which would make an ideal landing site, with perhaps 400m length available. On the downwind, thinking I was going to immediately land, I flew too far away from it to set up a more controlled final approach, and the instructor claimed I’d lost sight of it and couldn’t inspect is properly. In retrospect, I disagree: I’d had a very thorough look at it on crosswind and early downwind, and maintained constant awareness of it. But the instructor also didn’t explain that we wouldn’t practice the approach on this pass: the idea is to do one circuit with a low-pass for inspection, go around and land the second time. Anyway, continuing the approach would have flagrantly violated to 500ft rule, so we climbed back up, went around a second time, but departed from the crosswind. There was a field of sheep under crosswind, but fortunately the aeroplane was quieter there since the engine was idle. Don’t want to upset them, now.

I’ve just remembered that I didn’t select carb heat when I descended. Probably not a huge deal since the engine was only at idle for a short time (400ft descent). But I’m still not in the habit of selecting it whenever I throttle back. Not good.

We climbed back to altitude and headed towards Chipping Norton. The instructor put us into a spiral dive and asked for a recovery. I recovered, but started to roll out before killing throttle: not quite right, I should kill the throttle quickly. But hardly a challenge.

And so back to base. The chimney at the quarry just north of the airport stood out in the low evening sun like a beacon from fifteen miles away, so I just pointed us at it. As we tracked towards it, the instructor suggested that it would be really annoying if the chimney had relocated to the middle of Brize Zone. I retorted that it would be more difficult to mysteriously relocate Farmoor Reservoir, brightly visible in the two o’clock position from our course of about 110 degrees, and the illuminated monolith of the John Radcliffe Hospital gave additional confirmation of position. He conceded.

About four miles out, with the airfield now clear, I changed track towards it and the instructor requested a practice forced landing from the overhead. That’s fun, then. He claimed I was drifting too much to the right as I approached the airfield, and he was probably correct. Overhead the airfield, he shut the throttle, and it was time to get it down.

Got 75 knots set without too much trouble. After brief confusion caused by inability to see the airfield directly beneath me, I orientated myself with the familiar local landmarks, noted the altimeter, and set about planning the descent. It all went brilliantly to plan - except that after that confusion, and being in “I’m landing on an airport runway” mode, I completely forgot to do the PFL checks. Error! Anyway, I had 1000 feet half-way down short base, 800 feet on one mile final, and seeing the numbers slipping towards the cowling I put in a single stage of flap: the numbers anchored themselves on the windshield, and I flared bang over them at 75 knots. I touched down a little too fast though, since I didn’t have the usual effect of cutting the throttle during the flare to slow the aircraft down. The aircraft bounced on its main wheels, and I made the cardinal sin of releasing a touch of back pressure as a consequence. I guess I was afraid of it bouncing significantly back into the air as a consequence, a bad consequence when there’s no engine available to catch a bounce. It only bounced a foot or two, and the resulting landing from the bounce was gentle, but the principle is bad. The instructor claimed that if I’d held the nose attitude during the bounce, it would have touched down gently without endangering the nosewheel. I don’t completely understand, though. One to ask them next time.

Dead donkey

Monday, September 3rd, 2007

Flying time today: 1h 0m

Total flying time: 24h 50m

Today was all about practice forced landings. So we did the briefing: when the engine stops, it’s time to…

  1. FLY THE AEROPLANE! Hold level until speed backs off to 75 knots, then drop into a glide descent trimmed for 75 knots.
  2. Figure out which way the wind is blowing on the ground, and turn *downwind* to extend the glide range. Not into wind, as I mistakenly had in my head (that comes later).
  3. Find a place to land. You’re looking for a place that’s visible lower than 10 degrees from the horizon: use the outermost line of wing rivets as an approximate reference. Try to find a field surrounded by good alternates, and keep eyes out for power lines.
  4. Figure out what the path over the ground is going to be from the current “downwind” position, and identify uniquely-identifiable landmarks to mark the position of base and final turns. The aim is to be over the base turn landmark at 1000ft AGL: typically 1300-1500ft QNH in north Oxfordshire.
  5. Go though the engine failure checklist, to see if the problem can be rectified.
  6. If not, do a Mayday call on the last-used frequency, or on 121.5: “Mayday Mayday Mayday, Golf Alpha Bravo Charlie Delta is a PA28 with engine failure, one thousand feet over Hinton in the Hedges, making forced landing, 2 POB”.
  7. Turn final, do the “committed” shutdown checks.
  8. If high, use flaps or S-turns to lose height. If low, use an alternate landing area.
  9. Land well… and be lucky.

So we made a prompt start to head out to north Oxfordshire again, climbing up to 3500ft to get ready for the drill. I must remember to dip or swerve the nose every few hundred feet when climbing out, to look out for traffic. It was another beautiful evening, and I could even make out the Malverns and Brecon Beacons on the western horizon.

The instructor pointed us nowhere in particular around Barford St. John at about 3500ft, and shut the throttle. Got control of the plane and trimmed it nicely, and looked out for a site. Spotted a nice-looking field after a bit of confusion about the wind, visualised an approach course and spotted suitable landmarks to keep aligned with. The only snag was, I judged the descent rate based on my circuit experience of approaches with a functioning engine! As I proceeded through the checks, it became clear that I’d reach the ground about half-way along base leg, a mile short of the chosen field… a good lesson learned about glide approaches! We went around early: I’d well and truly got it wrong. So we climbed back to altitude, and the instructor pointed us towards the airfield at Hinton-in-the-Hedges. Did a much better job of it this time: the approach was made more difficult by arriving directly above the “chosen field” at the point of engine failure (you wouldn’t normally select a field that was invisible to you at that point!) - but nonetheless I set up the approach well. Arrived somewhat too high, went through the drills just fine, and got it down about half-way along the shortish runway with the aid of lots of flap. With a functioning engine I wouldn’t have landed as the braking distance on grass would have been very iffy… but crashing into a hedge at ten or twenty miles an hour isn’t a big deal compared to hitting a tree at 60, or stalling at a hundred feet!

Went-around, and did another one into Hinton-in-the-Hedges. Similar deal, doing a PFL from the overhead so not really practicing the proper circuit pattern, but it was good for judging the glide descent nonetheless. It’s actually easier to judge than I’d expected, after my initial mistake. Always err on the side of caution when judging the approach: there are manifold ways of rapidly losing height (flaps, S-turns, side-slips), but none of getting height back when the engine’s dead! This one went fairly well, too: went-around at about twenty feet.

So it was time to head back to Oxford. The instructor obtained permission from ATC to do a PFL from the overhead - so we positioned at 3000ft on the dead side of the airfield, the instructor shut the throttle, and I had to get it down! With no engine from that point, I managed to flare it bang over the numbers for a good landing - which I’m pretty pleased with. A 180 degree turn loses 500 feet (and a 360 loses 1000ft), so with a turn to right downwind, a moderately conventional base/final approach, one stage of flap and a single S-bend on final, we were on exactly the right descent profile on short final.

I’ve now got a good idea of the glide angle, and ways to steepen it. The whole thing is far less difficult than I imagined - though when the engine is really dead and I’m sh!tting myself in fear of imminent mutilation, it may be a little more challenging! Apparently, that’s all the actual lesson time I need to do for PFLs - although instructors will randomly throw them in during lessons to surprise me! Better keep my hand on the throttle in future…