The ILS 19 to Teterboro is my favorite approach to the airport because it is about the only one there with no drama. But it overflies some noise sensitive areas so we are being encouraged to fly the RNAV(GPS) X Rwy 19 instead, especially at night.
We decided to give that a test on a clear day. Here is what we found.
The approach brings you in at a 13° offset, so it still qualifies as a "straight in" approach. The minimums are 1000-3 for a Category C or D aircraft. But if you examine the approach path between DUUNE and the runway, you will see the problem. It is a tower at 693' during your descent from 1,500' at DUUNE to the runway at 6' MSL. The locals know this as the ABC Tower.
We picked a good weather day and gave it a try:
I was uncomfortable staying on the approach centerline all the way to DUUNE, so we broke it off and flew to the extended runway centerline while descending on a 3° path to the runway. I thought we were below the antenna's height when abeam it. It looks that way on the video.
I got the coordinates for DUUNE from the FAA data base: N40° 55' 48" W74° 4' 24" which converts to N40.93° W 74.073333° in decimal units if you want to enter this into GoogleEarth yourself. I was given the coordinates for the ABC Tower: N40° 52' 50.4" W74° 04' 00.5" which comes to N40.8805556° W74.0691667° in decimal.
Using GoogleEarth, we see DUUNE is 4.5 nm to the runway and the ABC Tower is 1.54 nm to the runway.
Drawing a line from the tower to the touchdown point on Runway 19 shows it is 1.54 nautical miles. Doing the math (shown on the illustration) we see our path puts the aircraft at 490' with the tower at 693' so it is a vertical threat if we are off course. By how much?
If you were to fly the RNAV(GPS) X Rwy 19 precisely on course, the tower will be to your right 0.25 nm.
I would treat this approach like I treat most approaches at many Colorado mountain airports, such as Eagle or Vail. I would not descend below 1,500' at DUUNE unless I had the runway in sight and I would offset at that point.
I would also require the PAPI be in view. It is very hard to establish a vertical path. If your aircraft permits a quick change to the ILS, that would be very helpful. That is a bit cumbersome in the aircraft used for the video, a Gulfstream GVII. But our advantage is that we did have an extended runway centerline, a flight path vector, and a VPATH line viewable in the HUD.
Can you do this at night? Sure, you can. But offset no later than DUUNE. Me? I don't think I'll ask for this approach again and if they assign it to me at night, I would say "unable."
Of course all this begs the following question: will the early offset achieve the noise abatement aims of the approach? I don't know.
Copyright 2019. Code 7700 LLC. All Rights Reserved.