Recently while researching components of an ILS online I came across pilotfriend.com.  It’s a site in the UK that serves as a portal of information related to all things aviation. On one page I found a long list of instrument related tips and pointers. When I say long, I mean it took almost an hour to read the whole thing. It was all pretty good, but I’ve compiled the items that really caught my eye below. Some of these relate specifically to instrument flying, while many are just good common sense.

1. •Single pilot IFR is ten times more difficult than two pilot IFR. Even with an autopilot, single pilot IFR requires more practice and proficiency than is required when two pilots divide the work load.
   

1. •Review your pitch and power setting for every stage of the approach. Remember: Wind will never be what they say it is.
   

1. •Use All Your Navaids.
   

1. •Inside the marker you just listen to ATC.
   

1. •Middle marker inoperative does not change minimums as of 1993. Check the marker crossing altitude as an altimeter check. The middle marker is not a required component for full ILS minimums nor for the localizer.
   

1. •One mile out one degree is 100' or one dot. Two dots equal 200'. ATP standards are one dot deflection calls for a missed approach.
   

1. •Inside the marker pitch to glide slope and use rudder for localizer.
   

1. •Localizer's full deflection is 350' to each side of the center line at the runway threshold. Glideslope:  At the threshold the full deflection will be close to five-feet. At the middle marker it is 200'.
   

1. •For a localizer type approach, select a vertical descent that will get you to the MDA about one minute before the projected time that the MDA runs out.
   

1. •Don’t chase ILS needles because you will always tend to over-react. If you find yourself doing this, once you have over-reacted immediately take out at least half of the initial reaction.
   

1. •Use GPS to determine wind correction angle. GPS shows ground speed.
   

1. •Always have the plane trimmed for an airspeed hands off. Any change in power (descent rate) will require trim change. Don’t trim immediately on making a power change.
   

1. •Do not look for the surface on an ILS approach until you are within 100’ of your personal minimums. Lock your arm and elbow before looking or you will probably need to make a heading adjustment on coming back to the instruments. At 100’ above minimums, don’t look too long or you will bust minimums.
   

1. •Rule of thumb for ILS descent (FPM) is to multiply your ground speed by 5.
   

1. •Losing the G/S once you've descended below the MDA requires an immediate missed approach. If you should lose the ILS glide slope it is best to execute the missed rather than change to the LOC. Make the missed and shoot the LOC as planned from the beginning after confirming that the minimums will give you a good shot.
   

1. •You are off altitude when ATC makes a query. Fix it and then respond. Don’t put anything on tape you don’t want ATC to hear.
   

1. •Most ILS accidents (20-30 per year) seem to occur within a mile or less of the runway but 30% crash on the runway. Over 50% of the accidents occur at night when only 25% of the ILS approaches are made. Transitioning to the visual is the most demanding and dangerous part of an ILS but even more so at night. There is no margin for error in an ILS.
   

1. •15% of ILS accidents occur while making second or third approaches. An ATC warning of course or altitude is sufficient notice to begin the missed.
   

1. •Compass turns can be made by time with a standard rate of 3 degrees per second.
   

2. •When turning Northerly, undershoot the heading by the latitude in degrees (34) plus half of the bank angle.
   

3. •When turning Southerly, overshoot the heading by the latitude (34) minus half the bank angle.
   

4. •When turning East or West from the South roll out 5 degrees early.
   

5. •When turning East or West from the North roll out 10 degrees early.
   

6. •
   

7. •The Glidepath Is Not a Glide slope
   

8. •A glide slope provides vertical guidance such as the VASI, PAPI. ILS, MLS and PAR
   

9. •A glidepath depicts the vertical descent profile of an approach.
   

1. •The most hazardous phase of the ILS is the transition from the instruments to the visual approach. A major part of the hazard is related to the pilot’s instinctive need to descend in reaction to an illusion of pitching up. This illusion is compounded by darkness, fog or haze. Poor visual cues at breakout can cause dangerous altitude deviations. Illusions become more likely the worse the visibility.
   

1. •Approach lights give no vertical reference. Flashing lights can disorient. Any loss of reference that results in instability of the approach can be disastrous. Loss of visual reference is most likely to cause instinctive reaction to pitch forward and down. The best security lies in having and using a VASI.
   

1. •At a typical DH of 200 feet, each dot represents 10 feet of extra altitude. If you extend a 20:1 glide path from that point to the runway, that'll work out to landing 200 feet beyond the

   

   touchdown markers. Even if you crossed the theoretical MAP (i.e. about a half mile from the threshold) with a full-scale fly-down indication, you'd be only 50 feet too high, which would correspond to landing 1000 feet past the landing zone (i.e. 2000 feet from the threshold). On any runway big enough to have an ILS, landing a light plane 2000 feet beyond the threshold should pose no problems getting stopped in time. Looking at it another way, even at full-scale fly-down deflection at DH, you're still lower than you would be on a typical visual approach!
   

  ---------------------------------------------------------

I particularly like the last item. It applies the glide slope theory to a real-world practical situation. Always strive for perfection in the approach, but also realize the implications of only being ½ to 1 one dot above the glide slope on an otherwise ‘perfect’ approach. Try it in VFR conditions so you’ll know what to expect the next time you need to get in at near-minimums!

© 2012 Garry Wing