One of the last weather-caused airline crashes in the United States was American Airlines Flight 1420 in Little Rock on June 1, 1999. As we mark its 20th anniversary, we’ll tie together some of the radar and thunderstorm skills we’ve learned in previous articles. You’ll also see brand-new radar scans of the storm from modern high-resolution display software—which is far more detailed than that in the NTSB report—and we’ll contemplate what you might see if you encounter a similar storm on modern radar today.
Among the caveats, though, is the fact that the guaranteed traffic separation works great with IFR aircraft, but not so much with VFR aircraft. On top of that, even those who always fly IFR must be in VFR mode at certain times, e.g. to depart and pick up a clearance, or to cancel IFR at or before the final landing phase. Even if you had those protections all the way in, though, you could be left to your own devices if VFR traffic conflicts occur. And they do.
Let’s start out with a few simple examples and work our way up. One of the most-used examples is, “Tower, Cessna 12345, ready for departure, Runway 14L.” “Cessna 12345, Tower, hold short Runway 14L.” The caution below appears on many charts, but have you really assimilated what it’s telling you? It’s simple. Essentially, if the controller says the word “runway” you should read back the explicit instruction: “Cessna 12345, holding short Runway 14L.” This is the proper way to respond.
A rriving at your destination on a dreary day, ATC queries you with “say approach requested.” The landing runway has an ILS and an RNAV (GPS) approach with identical LPV minimums published. Which do you choose? You would be forgiven for thinking, as we initially did, that this is a bit of an inconsequential question. WAAS has enabled satellite guided approaches to have precision comparable to Category I ILS approaches, so what difference does it make? Although true, this doesn’t mean that ILS and LPV are identical in all regards.
If issued an en-route clearance limit, you will be given holding instructions. If the pattern is charted, and they rarely are, you might be issued, “Hold east as published.” Most moving map displays such as the G1000 and GTN series do not show published holds, necessitating a chart, but ATC will issue full holding instructions if requested. The FAA frowns on unpublished holds, saying that “only those holding patterns depicted on U.S. government or commercially produced charts which meet FAA requirements should be used.” This is another reason why rolling your own at JIDUK, is a shaky idea.
A dmittedly, I’m an unabashed geek, getting my jollies running statistical tests querying the actual NTSB relational database and publishing my aviation safety research in journals using scientific mumbo-jumbo—the majority (if not all) of which would put any insomniac to sleep in a heartbeat. That said I’m also an active general aviation pilot. Here, I’ll don both hats as I cover a hot-off-the-press scientific paper published in the Atmosphere journal, “translating” from highfalutin language into layman’s English for the benefit of the general aviation pilot population.