ILS Back Course landing

Pro Member Captain
nottobe Captain

I flew to Nantucket Mass, but there was only runway 6 ILS backcourse landing. Everything was smooth until after it established the BC localizer, then I realized that there was no glide slope on my gauge. So I had no way to descend since the visibility was almost zero. Did I miss anything about ILS BC landing?

4 Responses

Don Wood Guest

You did not miss anything. Back course approaches almost never have glide slope information and, thus, are considered non-precision approaches. Where back course approaches are authorized, there will be a published minimum descent altitude and visibility. If you do not have the runway in sight when you reach that altitude in your descent or if the forward visibility is not at least the minimum specified, you are obligated to fly a missed approach. Also, MDA's for back course approaches and other non-precision approaches will always be higher than for ILS approaches. Sometimes the difference will be small - 100 to 150 feet. In other cases, especially where there are terrain conflcit issues, the differences will be greater.

Pro Member First Officer
Andrew (AJWatson2209) First Officer

is a backcourse ILS approach when the Localiser lights are at the other side of the runway?? (sorrry if im totally Off!)

Don Wood Guest

No, the ILS and back course have nothing to do with lights and I am not aware of any device called "localiser lights". You may be thinking of a light system called VASI or Vertical Aircraft Situation Indicator. That is not a component of an instrument approach. It simply gives a visual indicator to pilots on the approach of their vertical position relative to the ideal glide slope. You must be in visual contact with the runway to use VASI.

The Intrument Landing System (ILS) is a precision electronic radio system that provides both horizontal and vertical information about an airplane's position on the landing approach, relative to the ideal position for that approach. An ILS system is set up for a specific runway and is good only for approaches to that runway.

However, an aircraft approaching the opposite end of that runway can often use the localizer radio signals to establish its horizontal position on the approach relative to the centerline of the runway. That is called a "back course" approach. Back Course approaches provide no vertical indications and are thus, not a precision approach which is why the minimum descent altitudes are hiigher.

Pro Member First Officer
Ed Reagle (edr1073) First Officer

I deceided to take another flight today from KORF to KIAD. I set the course did all of the stuff the ATC told me to do. I got close to the ATC at Washington Approach I was vectored to runway 300. Hum there isn't an ILS equipment on that runway. I could still navigate but I could not do a A/P approach. With the little bit of experence with the ILS approaches that I've made to runway 1R and 1L, I told ATC as requested tell them when I have the runway insight. I replied and made contact with the tower for final. I took off the A/T and A/P and glided into the runway (300). Smooth landing and recovery on the ground. What I do not understand is the recommended configuration is @ 136,000 147 KIAS and @ 132,000 144 KIAS. In order for me to achive this landing and other I had to be on manual no A/P. With throttles at my control I noticed that I had to increase the throttles to about 73% to keep from running into the ground or at least keep from kissing the ground prematurely. But hey everybody walked away.


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