Readback: August 2019

In the Report Leaving article in February, the approach clearance with a vector to FALIX did not include a descent. Many years ago, I was taught to stay at the last assigned altitude until established on a published route. In this case, I guesstimate that you would have only a couple of miles, at best, to lose 1300 feet after intercepting the localizer.

Editorial Staff

Saturday, July 27, 2019 at 12:00 AM ET

Verified

Key Takeaways:

ADS-B traffic data can vary significantly in latency: TIS-B (ground re-transmitted) is 3-13 seconds old, while direct ADS-B (aircraft-to-aircraft) is practically instantaneous.
When ILS and LPV approaches have the same minimums, ILS offers greater resistance to wide-area GPS interference, though LPV generally requires less pilot input and aligns with the FAA's future all-GPS system plans.
An approach clearance that includes an altitude restriction (e.g., "Cross FALIX at 1700") permits descent to that altitude, provided it is at or above the Minimum Vectoring Altitude (MVA) in the vectored airspace.

See a mistake? Contact us.

Different ADS-B Traffic

“Sorting Out ADS-B” (February 2019) was a good overview, but readers should be aware that with TIS-B (i.e. where the aircraft position data is derived from re-transmitting from a ground station), re-transmission will occur either because (i) one aircraft is 1090 ES-equipped, and the other is on 978 or (ii) the threat aircraft is not ADS-B-out-equipped.

In either case, the location information displayed (via TIS-B) will be 3 to 13 seconds old. In contrast, where both aircraft are comparably equipped (e.g. both have 978 or both have 1090) location data via ADS-B traffic is practically instantaneous (once per second). I refer you to AIM (section 4-5-8) for further information.