Its certainly legal to fly through the AIRMET. These are advisories covering large areas. But it behooves you to determine that your flight plan wont enter known or forecast light or moderate icing conditions as prohibited in 91.527. Here goes. Theres a stationary front just west of the route, bringing in cloud layers and scattered showers. Freezing levels will hit between 7000 and 12,000 feet. So, at 8000 feet, you do risk picking up ice. One lone pilot report from a single-engine turbine over Iowa shows negative ice in climb from 3000 to the tops at 11,000. This isnt all that useful since youre flying lower and slower, but you are willing to climb as high as 12,000 feet to be on top. Your Plan B, while not at all mission-friendly, is to turn back to warmer air and land in Iowa, or even return to Bowling Green if thats best.
I used to fly out of an airport on the coast just south of the San Francisco Class B. While controllers tried to permit transit, there was no guarantee. If they also have a 91.131(a)(2) problem, that Miami solution would seem attractive to San Francisco. The result for VFR traffic on a trip headed north might be to add up to 100 miles or more to bypass the Class B to the east, or a deviation far out over the Pacific Ocean, neither of which is an attractive alternative.
It should be obvious that we never say the words, Declare, Emergency, Mayday, or Pan-Pan unless we indeed have a dire situation. These words have the potential to flip a controllers airspace upside down faster than a Vmc roll, so they should be used with discretion. Even saying Declare by itself could lead us to believe that assistance is needed, as well as Pan-Pan (Urgent condition). Because Pan-Pan is considered an urgent condition (maybe not a full-blown emergency), it has the potential to turn into Mayday (Distress) so we mostly treat it as such.
TCAS II is the most comprehensive form of TCAS, but its range depends on what it is asked to do. Overall pulse detection range is 30 NM for Mode S transponders and 14 NM for Mode A/C units. Surveillance must be reliable within 14 NM, but TCAS II will only assess threats within 12 NM as possible RAs. TCAS II guarantees system reliability within at least 4.5 NM. Two TCAS II systems can coordinate RAs to maximize vertical separation, typically 300-700 feet. There is even a reverse RA if one aircraft fails to respond correctly in the latest version 7.1 software.
Lets consider a situation. We are flying over the Florida Everglades in low IMC. Our alternator just died, which clearly counts as an emergency in IMC. So, we must land. Now! Wind is blowing from the west at 25 knots and we are close to Dade-Collier Transition and Training Airport (KTNT). Although it used to have three approaches to Runway 9-an ILS, an NDB and an RNAV-the only one now available is the RNAV (GPS) RWY 9 approach. With that wind, we certainly will not be landing on Runway 9, even though the runway is 10,500-feet long.
Time to check Off-Route Obstruction Clearance Altitudes. These start at 3400 to 4000 feet then quickly get up to 6000. The terrain continues to rise towards 8000 feet past Scottsbluff. Uh, were not in Minnesota anymore. OROCAs, as defined by the Instrument Procedures Handbook, are for situational awareness and emergency use. While OROCAs provide standard obstacle clearance margins (1000 feet in non-mountainous areas), you cant count on them. You decide its safest to file for 8000 feet.
We all have a different way to go about our flight planning, but most of it is along the lines of where to go, how high, how much fuel, weight and balance, etc. You factor it all into the plan, but at some point youll add that X for some bad weather and a re-route. Maybe the weather is fine where you are departing but not good where you are going, or vice versa. Depending on the mission, what are your options? It all comes down to a go/no-go on what youre comfortable doing and not doing. This is the typical process regardless of whether youre filing VFR or IFR.
Before you get a contact approach, some more boxes need to be checked, starting with weather minimums on par with Special VFR and Class G airspace. AIM 5-4-25 kicks off with them: Pilots operating in accordance with an IFR flight plan, provided they are clear of clouds and have at least one mile flight visibility and can reasonably expect to continue to the destination airport in those conditions, may request ATC authorization for a contact approach.
This is a long flight, so you want to minimize distance and go as direct as possible. You scan the route from TAFOY to KFSM on the chart, and it doesnt pass through any special use airspace (SUA), so you could go direct. But, you want to comply with the AIM guidance (see below) and pick a fix or two in each centers airspace. You zoom in on the chart to see TAFOY clearly, then just scroll the chart to the east along your route, looking for fixes on your route that you could add.
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, well tie together some of the radar and thunderstorm skills weve learned in previous articles. Youll 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 well contemplate what you might see if you encounter a similar storm on modern radar today.
Clearly, this was a humbling experience. Im left wondering how many of us who are more than a few decades and a few thousand hours past flying trainers at 60 knots would do better. Your takeaway from this self-deprecating story is that no matter what you fly, youve got to play well with all the others, be they fast or slow, pro or student. Im glad I relearned that lesson with no worse than some personal embarrassment. And, the students probably learned to watch out for fast twins with inattentive pilots.
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.