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Tuesday, November 13, 2007

In the business world, there are so many TLA's (Three Letter Acronyms) it is hard to keep them straight. But in aviation they are an important part of your ADM (Aeronautical Decision Making) and fit into your CRM (Cockpit Resource Management). I've even invented a few. Here is one of my favorites!

Instrument flying, especially solo IFR, can be a handful. Every technique that reduces your workload and helps you maintain procedures is a good technique. From the IAF (Initial Approach Fix) inbound to a landing or a go around from an instrument approach, there are some specific elements which must occur every time. The acronym HALFDARTS (think of half a dart flying to the airport) can help you when entering your approach phase. They are in he order I like to pay attention to them. I find in practice this flows well.

H -
Heading. Heading is certainly the most critical; if you are not heading towards the next fix, or the OM (Outer Marker) everything else is a mot point and you may be rapidly flying into danger. Remember that heading is not course. Heading takes into consideration any WCA (Wind Correction Angle) necessary to maintain your desired courseline, which only becomes more critical as you approach your landing zone. Take a moment to think about what headings you'll use, maybe dial a heading into your VOR/OBS; double check the Heading on your Heading Indicator, and look over any headings you'll need through the rest of the approach and the missed approach too.

A -
Altitude. Just as with heading errors, altitude errors can get you quickly into trouble, though at least you'll be on the right heading, right? Set your altimeter to the airport altimeter setting, and commit to memory the altitudes for each phase of the approach, including MDA (Minimum Descent Altitude) or DH (Decision Height) if it is a precision approach, and be sure to include your missed approach altitudes as well.

L -
Lighting. Why worry about lighting now? Because at this stage of the approach you have the mental bandwidth to set up the cockpit lighting the way you'll have best visibility during the approach and still be able to see outside for approach lights at breakout, You'll have the time to think about and set landing lights, nav and recognition lights, and think about whether you want strobes on or not, since they can be disorientating in clouds. While you are thinking about lighting, what is your emergency lighting plan? A lighting emergency on final approach won't be so bad if you can quickly put your hand on your flashlight.

F -
Frequencies. Run through and set your frequencies. If you pre-set frequencies, do so. I like to have approach and tower on the number one comm radio and ATIS / ASOS and ground control on the number two comm, but that's just my preference. I also like to use all nav equipment I have on an actual approach, so each receiver will be turned in to an appropriate frequency. If I have a number two nav not in use I'll set i to the ILS or approach course as a back-up, and I'll pay attention to the audio, testing and setting each with appropriate squelch levels, and leaving he audio on the primary approach navaid up just loud enough to hear the morse code identifier during the approach. No audible identifier, no reliable signal! If I have GPS I have it set up WAY before needing it and back it up with standard instruments as well.

D -
Distance. How far to the next fix? To the runway threshold? Down the ILS? To the Middle Marker? What's the distance from the runway to the missed approach fix?

A -
Airspeed. Memorize them, from initial approach to holding pattern entry and approach speed. What airspeed will you use climbing out on a missed approach? Airspeed is not groundspeed. Is the win helping or hurting you?

R -
Runway and Runway environment. Which runway will you land on? If parallels, Left, or Right? You did read your NOTAMS for runway conditions before takeoff, right? Take a second and look at the runway environment depicted on your approach plate an think about where the buildings are, the width and any slope of the runway, and how it might look on breakout (building to left or right?) to help with your pattern recognition on landing.

T -
Time. Needless to say,everything has a time and a place, and the place for timing is knowing by heart EXACTLY how much time each step down to MDA or DH will require. Keeping track of time can also help if you suffer any equipment failure during the approach.

S -
Safety. Never forge safety. Everything else is done, so apply your ADM skills and have your descent and landing checklist handy, and think through any other aspect of the flight which might have a safety component. Extra low ceilings or visibility, cockpit occupant safety (don't forget yourself!) and the safety aspects of the plane; carb heat, de-icing, and perhaps the biggest one of all; is the landing gear down?

HALFDARTS. A useful acronym I've used for years. I hope you like it! Please use it freely and post any comments back here if you felt it worked well or have suggestions for improvement.

Onwards and Upwards! Rob Bremmer


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