Flying the ILS - any good advice?

Find or share aviation knowledge
William Hughes
Senior Airman
Posts: 222
Joined: 13 Dec 2014, 11:38
Location: Saskatoon, SK
Contact:

Re: Flying the ILS - any good advice?

Post by William Hughes »

During actual approaches to a real airport with jet traffic you get asked to get your speed up. Even the FAF can be several miles out, and if you are going very slow with the wheels out and the flaps down and so on and so forth that means several minutes of slowly dragging your butt down the slope. If you do it as soon as you intercept final it could be even longer, and the field can't be used while that happens.

In the Comanche, I'll fly the approach at cruise speed, 145 knots, and start slowing down when on the final segment, and then really slow down and drop the gear and such when a few minutes back. Even then I'll keep the aircraft at 100-110 knots until visual transition. So for me it is a continual and gradual reduction in speed.

A lot of the focus about stabilized approaches is aimed at large heavy aircraft that cannot easily change their configuration and have a significant delay in applying power if required. A 3,000 pound aircraft can react almost instantly. So you want to be careful about applying technique designed for a specific type of aircraft to other aircraft.

Stabilized approach is good airmanship and I agree whole-heartedly with the concept. But physics is physics, too.

User avatar
Nick - A2A
A2A Captain
Posts: 13734
Joined: 06 Jun 2014, 13:06
Location: UK

Re: Flying the ILS - any good advice?

Post by Nick - A2A »

Thanks for the post William - always interesting to hear different perspectives on this. :) The method you describe is definitely consistent with how I'll typically fly a visual straight-in approach in the sim. Not for reasons of traffic separation as such, but largely because it's less time consuming than flying the last 5-6 miles at 90 KIAS or so. This kind of approach certainly keeps things more interesting too.

However, when flying on instruments, I find the workload is much higher when I try this, and the approach is much more likely to go awry. I'd guess (hope, anyway) that ATC tends to be pretty understanding of private aircraft flying single pilot IFR approaches in challenging IMC, and wouldn't try to rush or pressure them too much?

Also interesting to read your recent blog post on instrument currency / recency. I'll have to check out more of your posts. :wink:

Cheers,
Nick
A2A Simulations Inc.

User avatar
Great Ozzie
A2A Test Pilot
Posts: 2054
Joined: 16 Feb 2008, 15:49
Location: KUMP

Re: Flying the ILS - any good advice?

Post by Great Ozzie »

Nick M wrote: I'd guess (hope, anyway) that ATC tends to be pretty understanding of private aircraft flying single pilot IFR approaches in challenging IMC, and wouldn't try to rush or pressure them too much?
I never had a problem flying a Warrior or Cessna in Low IFR conditions. I don't think I used more than 90kts. Vfe for a Warrior is 103kias. I want to be 10kts or so underneath that so I can use 10° flaps for the approach... unless I am willing to fly it faster. Which means I will have practiced a no flaps approach at the higher speed - and am comfortable with it i.e. I know I am capable. No room for guessing here.

If the airplane is capable of more, you should try to be capable as well. But I would never let ATC push me into something I was not comfortable with. If they ask you what is your best speed, and for you (and the airplane) it is 90kts, then that is what it is. Let them know. If you cannot comply with their request, a simple "unable" is sufficient - if they need to resequence you, they will. Same thing if they say "best speed to the marker". I could say, "I can give you 110 to the marker and 90 for the approach" - again, only if I am confident with that.

When they ask, "say type aircraft" and you come back with something like "PA28 Alpha" (or Warrior) or "Cessna 172" they know what to expect. And I believe they would expect 90 to 100kts.
Rob Osborne
Flight Instructor - CFI, CFII, MEI, MEII
A & P Mechanic


FAASTeam - Safer Skies Through Education
Professionalism in aviation is the pursuit of excellence through discipline, ethical behavior and continuous improvement. NBAA

User avatar
AKar
A2A Master Mechanic
Posts: 5208
Joined: 26 May 2013, 05:03

Re: Flying the ILS - any good advice?

Post by AKar »

Great Ozzie wrote:If the airplane is capable of more, you should try to be capable as well.
I just recall a similar quote from the past from someone so well, that I need to re-quote yours again, Rob.

That should be on the wall.

-Esa

User avatar
Great Ozzie
A2A Test Pilot
Posts: 2054
Joined: 16 Feb 2008, 15:49
Location: KUMP

Re: Flying the ILS - any good advice?

Post by Great Ozzie »

Thanks Esa. I really appreciate that. Truly.

I'd reckon that would be a first for me. 8)
Rob Osborne
Flight Instructor - CFI, CFII, MEI, MEII
A & P Mechanic


FAASTeam - Safer Skies Through Education
Professionalism in aviation is the pursuit of excellence through discipline, ethical behavior and continuous improvement. NBAA

William Hughes
Senior Airman
Posts: 222
Joined: 13 Dec 2014, 11:38
Location: Saskatoon, SK
Contact:

Re: Flying the ILS - any good advice?

Post by William Hughes »

I have to add that I have never been hassled by ATC to keep my speed up when doing something difficult. When shooting a practice approach in visual conditions, yes, I have been occasionally been asked to keep it moving. Or a very strong hint that switching to a visual approach would be appreciated!

User avatar
AKar
A2A Master Mechanic
Posts: 5208
Joined: 26 May 2013, 05:03

Re: Flying the ILS - any good advice?

Post by AKar »

I recall someone who used to keep up his speed by himself, so to speak. On one occasion, a Falcon business jet was on ILS, keeping its regular pace when tower, I think two or three times asked him to keep up speed as long as he could due to fast traffic behind, and eventually that traffic to slow down if able for separation. It was him, doing his usual 235...240 knots or thereabouts until quite far in final. The amusing part was he was flying Piper Cheyenne. :mrgreen:

-Esa

User avatar
Nick - A2A
A2A Captain
Posts: 13734
Joined: 06 Jun 2014, 13:06
Location: UK

Re: Flying the ILS - any good advice?

Post by Nick - A2A »

AKar wrote:It was him, doing his usual 235...240 knots or thereabouts until quite far in final.
Well - that just makes me feel really inadequate, pootling down the glideslope at 75 KIAS! :mrgreen: Or could the chap in the Cheyanne see where he was going?

Nick
A2A Simulations Inc.

User avatar
AKar
A2A Master Mechanic
Posts: 5208
Joined: 26 May 2013, 05:03

Re: Flying the ILS - any good advice?

Post by AKar »

Many of those small turboprops, when handled correctly, are actually rather good planes to fly fast like that because they accelerate fast and also slow down & go down quite well in comparison to small jets for instance. Of course, with TPE331 engines one ends up "NTS'ing" when prop turns the engine, so PT6 would suit better for sportier descends.

I don't remember the conditions except that it was dark on ground, but I don't think it would have made any difference anyway. :mrgreen:

-Esa

User avatar
Nick - A2A
A2A Captain
Posts: 13734
Joined: 06 Jun 2014, 13:06
Location: UK

Re: Flying the ILS - any good advice?

Post by Nick - A2A »

Well, not quite up to doing the approach at 200+ knots yet, but having reinstalled Shadowplay, though I'd share a couple of vids of practice approaches from today.

Both at the same field (KHQM) with its 3.5° glideslope and weather 'artificially' socked-in right to minimums to give me the practice where I need it most: the last few hundered feet before the MDA. ILS approaches in IMC are potentially pretty boring video material, but it's just the last couple of minutes, from around 1000 feet AGL to touchdown.

First one is in the Cherokee and as you'll see, it's not very stable, particularly in terms of tracking the localizer. I get a bit high in the last few seconds, so a rather steep dive to the threshold follows. Most of my practice sessions have been in the 182 with its HSI, and it shows! :roll: I'll have to work on my scan in the Cherokee...

Video - A2A Cherokee IFR approach to minimums, KHQM ILS/DME RWY 24

In the 182, things go a little better but I still spend a lot of time naggingly below the glideslope. Why didn't I correct this a bit more promptly? Not sure really, and I'm sure this would have been a bust in a checkride. :mrgreen: You'll likely notice some other errors too: no timer started at the FAF, no HQM VOR tuned-in for the missed approach and transponder still set for European VFR. I, er, generally "don't bother" with ATC...

Video - A2A Cessna 182T IFR approach to minimums, KHQM ILS/DME RWY 24

I'm still having fun with this though, and will try to get in a few practice approaches each month. Videoing oneself is really helpful when working out what's going wrong, and any critical feedback from you guys is welcome as always. :)

Cheers,
Nick

User avatar
Great Ozzie
A2A Test Pilot
Posts: 2054
Joined: 16 Feb 2008, 15:49
Location: KUMP

Re: Flying the ILS - any good advice?

Post by Great Ozzie »

They both look very good Nick. Let me paste in a couple relevant sections of the PTS:

Instrument Rating Practical Test Standards - Task B: Precision Approach (PA) [p.36]

12. Maintains a stabilized final approach, from the Final Approach Fix to DA/DH allowing no more than ¾-scale deflection of either the glideslope or localizer indications and maintains the desired airspeed within ±10 knots.
16. Maintains localizer and glideslope within ¾-scale deflection of the indicators during the visual descent from DA/DH to a point over the runway where glideslope must be abandoned to accomplish a normal landing.

---------
Airline Transport Pilot and Aircraft Type Rating Practical Test Standards - Task C: Precision Approaches (PA) [p.56]

12. Maintains a stabilized final approach, from the precision final approach fix to DA/DH, allowing no more than one-quarter scale deflection of either the glideslope or localizer indications, and maintains the desired airspeed within ±5 knots.
16. Maintains localizer and glide slope within one-quarter-scale deflection of the indicators during the visual descent from DA/DH to a point over the runway where the glideslope must be abandoned to accomplish a normal landing.


So how far out you were on the localizer - just a dot in the Cherokee - was great. Airspeed control was right on (fantastic).

For the Cherokee, compare your heading correction at about 600' to that at beginning at about 280'. Not much correction was needed. You held the needles in tight to 280' - Mins are 216', so you were just about there.

Let me ask you, do you change your aimpoint to the end of the runway (i.e. the numbers) when breaking out - as opposed to the Aiming Point Marking a 1000' from the threshold?

One other thing I do for these practice approaches is to set up the localizer freq in Nav2. And you could put HQM (for the missed) in standby for both. Or HQM in "active" for NAV2 if committed to only the ILS.

Why didn't I correct this a bit more promptly? Not sure really, and I'm sure this would have been a bust in a checkride.
Yeah if you see something off, correct it asap. As far as bust, I don't think so... maybe a, "why did you wait so long" and a :?. What - just a quarter-scale deflection. Not bad man.

And 90kias isn't so bad, is it? :P
Rob Osborne
Flight Instructor - CFI, CFII, MEI, MEII
A & P Mechanic


FAASTeam - Safer Skies Through Education
Professionalism in aviation is the pursuit of excellence through discipline, ethical behavior and continuous improvement. NBAA

User avatar
Nick - A2A
A2A Captain
Posts: 13734
Joined: 06 Jun 2014, 13:06
Location: UK

Re: Flying the ILS - any good advice?

Post by Nick - A2A »

Rob,

Those extracts from the practical test standards are very interesting. I was under the mistaken belief that one-quarter scale (or half dot) deviation was enough for an instrument rating 'fail'. I didn't realise this standard represents a (significantly) higher level of accuracy required at ATP level. That's encouraging anyway! :)
Great Ozzie wrote:Let me ask you, do you change your aimpoint to the end of the runway (i.e. the numbers) when breaking out - as opposed to the Aiming Point Marking a 1000' from the threshold?
Well, in the approach I videoed in the Cherokee, I definitely changed my aiming point once I'd become visual with the runway threshold. I'd become a bit high on the glideslope in the final few seconds, and it looks like I deliberately pitched the nose down to aim at the numbers prior to flaring. This is bad technique perhaps? In the Cherokee the round-out was certainly a little 'notchy' with a slightly premature and firm touchdown; I think this is mainly because I realised I was too nose heavy in trim and was in danger of running out of elevator authority during the flare. You can hear the squeaking of the crank as I attempt to address this. :P
Great Ozzie wrote:One other thing I do for these practice approaches is to set up the localizer freq in Nav2. And you could put HQM (for the missed) in standby for both. Or HQM in "active" for NAV2 if committed to only the ILS.
Yeah, good point. Typically it seems an HSI-equipped 182T would have a glideslope needle for the NAV2 receiver too, presumably to provide a good level of redundancy. Then, in the event of abandoning the approach, it's just a case of hitting the transfer buttons on NAV1 (and 2). I say 'just', but I tend to find that even small tasks (example: muting the NAV1 morse ident) can cause those CDI and glideslope needles to, er, 'misbehave' when hand flying in IMC. I take some comfort from the fact that interacting with controls in FSX via a mouse cursor is probably more of a distraction than pressing buttons in the real deal. However, I've read of quite a few accidents where a comparatively minor distraction in IMC was enough to cause spatial disorientation which resulted in CFIT.
Great Ozzie wrote:And 90kias isn't so bad, is it? :P
No, indeed it's not. In fact I was surprised that the (admittedly modest) increase in speed didn't really seem to make much difference to my performance at all.

Anyway, thanks for the continued advice and encouragement. :D
Nick

User avatar
Great Ozzie
A2A Test Pilot
Posts: 2054
Joined: 16 Feb 2008, 15:49
Location: KUMP

Re: Flying the ILS - any good advice?

Post by Great Ozzie »

...

RE: pitching the nose down and aiming for the numbers, some so-called food for thought from this Avweb The Pilot's Lounge #80: The ILS -- That Last 400 Feet.
Nick M wrote: In the Cherokee the round-out was certainly a little 'notchy' with a slightly premature and firm touchdown; I think this is mainly because I realised I was too nose heavy in trim and was in danger of running out of elevator authority during the flare.
But but but... aren't we trying to run out of elevator authority in the flare? :shock: Nose heavy trim should only make it a bit harder.
Nick M wrote: Then, in the event of abandoning the approach, it's just a case of hitting the transfer buttons on NAV1 (and 2). I say 'just', but I tend to find that even small tasks (example: muting the NAV1 morse ident) can cause those CDI and glideslope needles to, er, 'misbehave' when hand flying in IMC.
Are you listening to the morse idents during the approach? Just need to do a quick ident before starting the approach, then shut it off. You can also i.d. the missed frequency. If you decide to put it in standby, I would re-identify it on the way there. You aren't really tracking anything at the moment of the missed. It's get the airplane climbing, cleaned up and trimmed heading to the VOR. All I'm thinking about really is "up, up and away" i.e. if you maintain your current track, that should suffice in the time it would take to get switched over to HQM. If you are not wanting to mess with the LOC in #2 i.e. concerned you might be a bit close to do what you need to fly the MAP - sure set up the missed in #2 well before you start the approach.
Rob Osborne
Flight Instructor - CFI, CFII, MEI, MEII
A & P Mechanic


FAASTeam - Safer Skies Through Education
Professionalism in aviation is the pursuit of excellence through discipline, ethical behavior and continuous improvement. NBAA

User avatar
Nick - A2A
A2A Captain
Posts: 13734
Joined: 06 Jun 2014, 13:06
Location: UK

Re: Flying the ILS - any good advice?

Post by Nick - A2A »

Great Ozzie wrote: RE: pitching the nose down and aiming for the numbers, some so-called food for thought from this Avweb The Pilot's Lounge #80: The ILS -- That Last 400 Feet.
Interesting article Rob, thanks. If fact, it addresses some of the questions I've been grappling with in terms of speed on the ILS. And indeed, it's true that I do exactly what the author warns against: chopping power once I'm visual with the runway environment, and ignoring the glideslope needle.
Great Ozzie wrote:But but but... aren't we trying to run out of elevator authority in the flare? Nose heavy trim should only make it a bit harder.
Yeah, careless phrasing on my part, but I think in the A2A Cherokee the limited elevator authority of the Hershey Bar wing, 'short stabilator' PA-28's is carefully simulated. In the sim, at any rate, I find that if there's too much nose-down trim during the flare, I'll run out of elevator authority prematurely (this being the key word I omitted), so can't keep the nose up as long as I need to, even with the yoke held fully back. (I appreciate that this is where FSX trim is starting to diverge from real life trim, as we can't increase our elevator authority with trim in the real thing. :wink: )

Actually, I think this excessive nose down trim was more of an issue in the ILS approach because typically my visual approaches in the Cherokee will tend to be steeper, slower, power-off approaches so I'll be trimmed for ~80 mph already.
Great Ozzie wrote:Are you listening to the morse idents during the approach?
Well, that was the problem: I had the morse ident enabled for when I picked-up the localizer, but the beeping was starting to irritate me so I switched it off. Fumbling around for the rather small click spot was surprisingly distracting in IMC! :roll: Incidentally, the MAP at KHQM is nice and easy isn't it? Just fly runway heading more-or-less towards the HQM VOR without any turns or terrain to worry about. "up, up and away" indeed! :)

Cheers,
Nick

William Hughes
Senior Airman
Posts: 222
Joined: 13 Dec 2014, 11:38
Location: Saskatoon, SK
Contact:

Re: Flying the ILS - any good advice?

Post by William Hughes »

Anything you can do to eliminate distractions, do it. You have to monitor an the ADF beacon inbound if it is part of the approach (FAF or the primary) but not the localizer. Up here half deflection is a fail on a check ride.

new reply

Return to “Flight Academy”

Who is online

Users browsing this forum: No registered users and 9 guests