I just read the Hannah post by dave over at Flight Level 390 and I have to say it was a lot of fun. FF's LIFR and IFR flight assignments are tailored for the bad weather enthusiast, and I'll share mine and others experiences in the wet and bumpy. In the meantime check it out: "The co-pilot tears off the latest weather from the mini-printer and reads it: Winds 130 degrees at 25 gusting 35 kts. Heavy rain. Ceiling 800 overcast. Visibility 1 mile. Altimeter 29.65 and falling."
Hannah
Tuesday, September 23, 2008
Sunday, September 14, 2008
Auto Refresh Implemented
Assignment pages now have a built-in auto-refresh capability. This way if you are interested in say, only IFR flights, then you can load the page one time and let it idle in a separate tab. As the flight assignments change the page will refresh periodically with the updated information. Mobile pages do not have this capability (who keeps their iPhone plugged in all the time?)
Friday, September 12, 2008
Hurricane Ike
Currently, Hurricane Ike is the big story along the Northern Gulf of Mexico, so this weekend FourFlights will focus on flight assignments in Texas, Louisiana, and Mississippi.
The latest data for the Houston terminal area is winds from 050 at 19 gutsing to 26 knots, visibility 10 miles, overcast at 4000 - I bet Hobby Airport is making good use of Runway 4!
Wednesday, September 10, 2008
Rules of Dispatch
One of the first rules that FF Dispatchers learn is to select departure airports that are within what we call dynamic weather range (DWR) of the destination airport. The DWR is typically a distance that equates to an estimated time enroute (ETE) of about one hour. The idea behind a dynamic weather range is to dispatch a flight that will terminate with an approach into the selected weather conditions. For example, if you select a VFR flight then you'd like conditions to be VFR as you enter the terminal area.
The rule of thumb used to calculate estimated time enroute is to multiply the straight-line distance (in nautical miles) times 0.15 and add 30 minutes. For example, a flight from Orlando (KMCO) to Miami (KMIA) is 167 NM. The ETE is 167 * 0.15 + 30 minutes which is about 55 minutes. The nice thing about this formula is that it accounts for ground operations. This works out pretty well for commercial jets and probably turboprops on shorter flights (but probably not as well for piston aircraft like a Cessna 152).
Flight assignments will almost always originate with weather conditions as good or better than at the destination. What this means is that a VFR flight will almost always start VFR, but an IFR flight could start out with VFR, MVFR, or IFR weather conditions, but never LIFR, at the time of dispatch. Additionally, IFR and LIFR flights with arrival conditions that include rain, snow, and/or thunderstorms have higher priority - this makes for a more challenging flight, don't you think?
At this hour there are 28 stations reporting IFR in the universe of Part 139 airports in the continental United States, but only 8 are reporting rain. The one that was selected was Newport News with winds from 040 at 5 knots, and visibility 1.5 miles in light rain and mist. If you're looking for rain you came to the right place!
The rule of thumb used to calculate estimated time enroute is to multiply the straight-line distance (in nautical miles) times 0.15 and add 30 minutes. For example, a flight from Orlando (KMCO) to Miami (KMIA) is 167 NM. The ETE is 167 * 0.15 + 30 minutes which is about 55 minutes. The nice thing about this formula is that it accounts for ground operations. This works out pretty well for commercial jets and probably turboprops on shorter flights (but probably not as well for piston aircraft like a Cessna 152).
Flight assignments will almost always originate with weather conditions as good or better than at the destination. What this means is that a VFR flight will almost always start VFR, but an IFR flight could start out with VFR, MVFR, or IFR weather conditions, but never LIFR, at the time of dispatch. Additionally, IFR and LIFR flights with arrival conditions that include rain, snow, and/or thunderstorms have higher priority - this makes for a more challenging flight, don't you think?
At this hour there are 28 stations reporting IFR in the universe of Part 139 airports in the continental United States, but only 8 are reporting rain. The one that was selected was Newport News with winds from 040 at 5 knots, and visibility 1.5 miles in light rain and mist. If you're looking for rain you came to the right place!
Tuesday, September 9, 2008
fourflights.com is up!
fourflights.com is a website that delivers flight assignments based on current weather conditions. That is what this blog is about. Every hour, dispatchers update the website with flights to airports with four different flight rules: LIFR, IFR, MVFR, and VFR. If you're a pilot you probably know what this means:
LIFR - Low Instrument Flight Rules
These are really poor conditions for even experienced instrument-rated pilots to land aircraft. A lot of times flights to airports with LIFR require a CAT II or CAT III aircrew certification (more on that in a later post). LIFR is a subset of IFR.
IFR - Instrument Flight Rules
This is no cakewalk and requires special training. Conditions that require instruments (avionics) to complete a flight are usually because of poor visibility and/or low clouds.
MVFR - Marginal Visual Flight Rules
A subset of VFR, conditions do not legally require IFR, yet are probably too challenging for visual-only flying.
VFR - Visual Flight Rules
This is the "see-and-avoid" kind of flying at its most basic. Clouds are no lower than 3000 feet above ground level, and visibility is more than 5 miles (and usually more!)
Here's a chart for comparison.
Stay tuned to this blog for updates and more information about fourflights.com
LIFR - Low Instrument Flight Rules
These are really poor conditions for even experienced instrument-rated pilots to land aircraft. A lot of times flights to airports with LIFR require a CAT II or CAT III aircrew certification (more on that in a later post). LIFR is a subset of IFR.
IFR - Instrument Flight Rules
This is no cakewalk and requires special training. Conditions that require instruments (avionics) to complete a flight are usually because of poor visibility and/or low clouds.
MVFR - Marginal Visual Flight Rules
A subset of VFR, conditions do not legally require IFR, yet are probably too challenging for visual-only flying.
VFR - Visual Flight Rules
This is the "see-and-avoid" kind of flying at its most basic. Clouds are no lower than 3000 feet above ground level, and visibility is more than 5 miles (and usually more!)
Here's a chart for comparison.
| Category | Ceiling (feet) | Visibility (miles) | |
| LIFR | less than 500 | and/or | less than 1 |
| IFR | 500 to 1000 | and/or | 1 to 3 |
| MVFR | 1000 thru 3000 | and/or | 3 thru 5 |
| VFR | more than 3000 | and | more than 5 |
Stay tuned to this blog for updates and more information about fourflights.com
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