Instrument Landing System

Last Friday (9th) I had my last lesson in the Seneca.  I flew to Birmingham for a radar vectored ILS approach.  Thanks to my failure of keeping this blog up to date, I haven’t described what an ILS is.  As a simple and brief introduction, here is a paragraph from Wikipedia:

An instrument landing system (ILS) is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument meteorological conditions (IMC), such as low ceilings or reduced visibility due to fog, rain, or blowing snow. For further reading click here.

The information provided by this system is presented to the pilot on an instrument called a HSI (Horizontal Situation Indicator).

Above is a typical HSI.  Very similar to the one we have in the Seneca.  When the ILS is tuned in on Navigation Radio 1 (NAV 1) and the aircraft is within range, the yellow indicators will show where you are in relation to the centreline of the runway and the correct descent path.  When setting up for the approach you put the course select pointer on the runway heading.  Both the course deviation bar and the dual glide-slope pointers are ‘fly to’ indications meaning that if the glide-slope pointers are above the middle point, then you need to decrease your descent rate until they are back in the middle.  Don’t climb on an ILS, it would just make it rather more difficult!  Similarly, if they were below the middle point, you would need to increase your rate of descent to get back on to the correct approach profile.

If the course deviation bar is to the left, it means that you are to the right of the runway centreline and that you need to fly left to correct it.  As you get closer and closer to the runway, these indications get ever more sensitive.  Throughout the approach we are to maintain the localiser (centreline) and the glide-slope to within half scale deflection.  Going outside these limits would result in a fail for the precision approach section.  On the CDI, half scale deflection is 2.5 dots left/right and on the glide-slope indicators half scale deflection is the next marker above/below.

There are two ways of doing such an approach.  One way is procedural and the other is radar vectored.  Most of the time we can get a radar vectored ILS which means the approach controller directs you on to the runway centreline using radar vectors.  Radar vectors are heading instructions given to the pilot by the approach/radar controller.  The final heading they give you is usually a 30 degree intercept to the localiser.  It is then the pilots responsibility to intercept and maintain the localiser and glide-slope.

The approach is flown with reference to an approach plate.  Please note: plate use with permission; neither the CAA or NATS accept any liability or responsibility for the content of the information; plate is for information purposes only and not intended for operational use.

The plate above details all the information to carry out either a procedural or a radar vectored ILS approach into Birmingham using runway 33.  As stated earlier, when being radar vectored, the controller will direct you towards the inbound track of 328 degrees.  The pilot then follows the recommended profile glide-path which is detailed on the plate just below the area diagram.  DME I-BM is your DME distance from Birmingham and below that are the recommended altitudes for the relevant distances.  Checking these as you go down the approach verifies that you are on the correct glide-path and that your altimeters are set correctly.

When carrying out a procedural approach you would navigate to the BHX (an NDB on Birmingham’s airfield) when cleared to do so and then hold over that beacon until cleared for the approach.  The hold is shown on the chart as right hand and with an outbound track of 328 degrees and an inbound track of 148 degrees.  When cleared for the approach, category A aircraft (the Seneca is category A) fly outbound from the BHX on a track of 160 degrees to D7 (7 miles DME) and then turn back inbound to intercept the ILS.  This way the pilot it entirely responsible for positioning for and intercepting the ILS.  Being radar vectored is much more convenient!

During lessons this approach is flown with the screens covering the windows so we cannot use any outside references.  We use plates that are provided by another company and different minima are specified.  The approach is essentially the same.  The plate is used states that I can descend to 530ft (DA – Decision Altitude) on the approach which would put me at 204ft above the runway surface.  Oxford Operating Procedures state that 20ft must be added to ILS minima to compensate for errors that could be shown by the instruments with the aircraft in it’s landing configuration making the DA 550ft for Birmingham.  At decision altitude there are two options, land or go around.  Land if you’re visual with the runway, go around if you’re not.  We always leave the screens up to simulate still being in cloud at this point and so our ILS approaches always result in a go around.  There are go around instructions on the plate which are followed unless otherwise directed by ATC.

Oxford to Birmingham

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Yesterday afternoon I flew from Oxford to Birmingham – and back again – as a passenger.  It’s always useful to sit in on others lessons to learn from their strengths/weaknesses and to also listen to the air traffic control.  There is a lot more  talk about in instrument flight and it’s taking some getting used to so I’ll take all the radio chatter I can get.  Another advantage of being a passenger on a training flight is that you can see!  England looks magnificent from the air, something that you miss when you’re the pilot because you’re behind the screens.

The prop looks pretty crazy on this picture of the left hand engine!

Birmingham director had us fly a 360 which took us over Coventry airport. A Swissair 146 landed before us and a Ryanair 737 afterwards.

No, nope. No-one has messed up my front lawn.

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Circuits – AP12 & 13

Staying in the pattern (flying circuits) is the best way to practice landings because you get a landing in every five minutes or so.  The video above shows one of those circuits.  It’s not me flying but it shows what I was doing moments earlier.

 

The basic left-hand traffic pattern.

The basic left-hand traffic pattern.

The traffic pattern is pretty simple.  It can either be left-hand or right-hand.  Sometimes both circuits run at the same time depending on how ATC are running things.  A normal circuit only takes about five minutes so you can get plenty of landing practice in a single lesson.  The pattern here at Goodyear is flown at 2000 feet above mean sea level.  On the ground you are already 968 feet above mean sea level so the pattern is 1000 feet above ground level.  You fly the upwind to 500ft and then turn crosswind, still climbing.  Upon reaching 2000ft level off and if you haven’t already, turn for the downwind leg.  The downwind leg is flown about one mile away from the runway.

When the touchdown point on the runway is about 45 degrees behind your wing, that is a good time to turn onto your base leg.  When turning base reduce power and set flaps to 25 degrees to assist with altitude loss and slowing down.  Turn onto final and set flaps to 40 degrees – maintain 70kts until over the runway.  When over the runway, reduce power to idle as appropriate and raise the nose (flare) for touchdown.  As you probably heard on the radio there was a quick chirp from the stall warner just before touchdown.  That’s pretty much how you want it to be.  You don’t want to stall any higher than just above touch down!

This is the view of the runway on the base leg.

This is the view of the runway on the base leg.

Turning onto final.

Turning onto final.

If you look at the full size version of the ‘final’ picture (by clicking on it) you will see the PAPIs (Precision Approach Path Indicators) on the left hand side of the runway.  These help in setting up the correct descent rate when approaching the runway.  What you want to see is white on the outside and red on the inside.  That shows you’re on the correct glide path.  Two whites tell you that you’re too high and two reds tell you that you’re too low.

Effects of Controls & Straight and Level

Me with the wee Warrior.

Me with the wee Warrior.

My next two lessons (AP2&AP3) covered effects of controls and straight and level as the title of this post suggests.  I was a little nervous about the second flight because of the nausea thing but it wasn’t an issue.  Both lessons were very smooth because they were the first of the day.  A favourite part of both of these lessons was taking off.  Even though the wee warrior doesn’t have the same acceleration as a passenger jet it is still really satisfying to push the throttle forwards and accelerate towards rotation speed (the speed where you lift the nose off the ground) which is 65kts in the Warrior.

B-E-A-utiful view! Kind of looks like Sim City from up here.

B-E-A-utiful view! Kind of looks like Sim City from up here.

My lessons are usually back to back with my two flying buddies so our instructor will do one flight after the other.  If the first two pilots go together on the first flight, we can land away at another airport, switch, and have the second pilot fly back to Goodyear and then the third pilot gets his flight.  I hope you followed that!  On AP3, we landed at Mobile which is about 20nm south/south-east of Goodyear.  It is insanely quiet out there, the airport is un-manned and the only other thing nearby is a landfill and I couldn’t even hear that.  I haven’t landed yet but I look forward to it.  It looks like quite the challenge!  Taking off isn’t terribly difficult, keep the nose on the centre line with the rudder (requires right rudder due to various forces acting on the plane) and rotate at 65kts.  Hold a slight nose up attitude to climb away but not too steeply.  Keep your hand on the throttle until 1000ft above the ground – that isn’t strictly essential in a single engine aeroplane, it’s more preparation for flying a twin.  If you have an engine failure on takeoff in a twin, you want to throttle back the live engine straight away.  You can’t do that unless your hand is on the throttle.  It’s fun and I’m looking forward to the challenge of landing.  Unfortunately it isn’t as simple as taking off – but then it wouldn’t be a challenge.  AP4 will be tomorrow morning – climb, descend and medium turns.

Straight and level was a good lesson for getting to know the area better.  There’s not much else you can do going straight and level for over an hour!  We did turn, just not very often.  The aim of the lesson was to be able to hold altitudes (using trim) and hold headings using references on the ground.

Who said there was a 'right' way up anyway?

Who said there was a ‘right’ way up anyway?

I was out at an RC flying club this morning – my first time ever to such a place.  It was a lot of fun too even though I didn’t get to fly.  If I was even allowed to fly the pictured aircraft above I would have said no right away.  The risk of messing up is way too high!  The pilot of the blue plane has been flying RC aircraft for about thirteen years and that is clearly visible when watching him do that flying thing.  He had it upside down, spinning, looping, ‘hovering’ and flying sideways.  The performance was a complete show stealer, everyone stopped to watch and for good reason too, it was very impressive!  He was just as good with RC helicopters too, I had no idea they were so maneuverable – or strong enough to withstand such insane flying.

Helicopter or lawn mower? Both!

Helicopter or lawn mower? Both!

Right, that’s it.  I’ll let you know how tomorrow goes.