If you are contemplating using a Sectional,
read this brief tutorial!
Helicopter Emergency Medical Services (HEMS) A021 VFR Compliance
A021.i(1) VFR Flight Planning states “Prior to conducting VFR operations under these Operations Specifications, the pilot must determine the minimum safe altitudes along the planned enroute phase of flight.” It further states that the minimum safe cruise altitudes are determined by evaluating the terrain and obstacles and then to fly specified minimums above both the terrain and obstacles.
The only means that the FAA provides to pilots that shows airports, terrain, and obstacles is a Sectional Chart or you could obtain both the FAA Airports database and the FAA Obstacles database and use that data to meet the requirement. Since the latter is probably beyond the resources of a HEMS base, let’s address the use of Sectional Charts.
It’s really very easy (at first glance). You locate you base and draw a line to either the accident scene or a hospital. Continue the next leg from the scene or hospital. And so on. Now you see if your route line crosses over any tower symbols (for that leg). If so, you must write down the tower height (AMSL value). After finding all the towers for that leg, you determine which is the highest AMSL tower. Next step is to again look along the route line for the topography to find the highest terrain and record that value. Repeat this for each flight leg. Also note that A021 calls for replanning should you have to deviate from the initial flight path.
Drawing a Route on a Sectional Chart fails to comply with A021
Why so? Let’s begin with the terrain contour lines. They are very hard to read. Imagine trying to trace or track a contour line to find the elevation value for every step of your flight path assuming you could even find the contour value. Of course, one way to “overcome” this tedious exercise is to simply use the Minimum Elevation Figure (MEF) as noted on the Chart for the quadrant. And if that quadrant has a mountain top that you route is not near, you will have to fly at some ridiculously high altitude.
It gets worse. Here’s the skinny that only a few pilots are aware of. Sectional Charts are designed for pilotage and should not be used to pinpoint objects. In other words, if you are at 2000 feet and use a Sectional, you can look down and know that there is a tower in the area you are approaching. THE TOWER, AS MARKED ON THE SECTIONAL, IS NOT EXACTLY POSITIONED ON THE SECTIONAL AT ITS TRUE LATITUDE AND LONGITUDE.
You know that Sectionals have both black latitude and longitude lines. They are very accurate but only so with respect to the underlying topography. Most of the roads, rivers, and other similar features are quite accurate. BUT TOWERS AND AIRPORT LOCATIONS ARE NOT. The FAA explains (National Aeronautical Charting Office) that when marking up charts every six months, airport markers and towers are moved around to make room for the additional reference text needed. They do their best to make the chart readable and as you know, Sectionals contain a wealth of information. NACO does an excellent job at this.
Based on our experience using Sectionals, if you wish to perform the VFR compliance portion of A021, you MUST, after drawing your route leg lines, span each line about 0.5 inches either side of the route line. This, to account for the fact that the airport location and obstacles locations are not accurately placed (in terms of their real latitudes and longitudes).
The Solution for A021 VFR Compliance
eSectionals is a General Aviation charting service and includes the FAA Airports and Obstacles databases as well as the National Elevation database. It includes two features, “Show Airports” and “Show Obstacles”. The illustrations that follow use the Washington Sectional with "your" base located at a Helipad (7MD3) just south of the Fort Detrick (MD32) marker printed on the chart.
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eSectionals(tm) SHOW AIRPORTS Note that Frederick Muni (FDK) as printed is over a quarter inch displaced from its real location. Also note that “your” base, Frederick Memorial Hospital (7MD3), a heliport, is not even printed on the Chart but is located by the airports database. |  |
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eSectionals(tm) SHOW OBSTACLES Note how many real obstacles are in the database that are not even printed on the Chart. It should be obvious that, without this feature, using a paper chart to comply with A021 fails to provide you with accurate information. |  |
With the Show Airports active you can easily locate your base and then draw a route line by clicking on that blue circle to place a depart point. If your first destination is an accident scene, given a latitude and longitude, you can use the Find LatLon feature to pinpoint that location and place a “waypoint” there. Continue with your leg to the hospital and then return to base. The following illustration shows one leg of this flight.
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eSectionals(tm) FLIGHT LEG In this example, the highest obstacle is both the highest AGL (magenta circle) and highest AMSL (red circle) obstacle. The red X also marks the highest terrain for that flight leg. |  |
The corresponding Route Report for this flight leg is also created.
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If the PIC desires, you can print the selected portion of the Chart and also print a Flight Profile.
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In the interest of both flight safety and HEMS compliance, that you understand the limitations of using a Sectional Chart. Make certain that you span your route line about at least half an inch either side of the line to record obstacles. You should also make certain that your Sectional Chart is not only current, but that you have manually marked up your paper chart with the latest FAA Chart Bulletins which add, remove, or update obstacle locations.