If you love math and solve complex word problems to relax, this article is NOT for you.
If math is a four letter word you sometimes use in conjunction with other more colorful four letter words, keep reading.

One of the most repeated questions in the air medical industry is how long?

How long until the helicopter gets here?

Everybody wants to know; the landing zone officer, communications center, county dispatch centers, advanced and basic life support ambulance services, first responders, even the nurse and paramedic on board the aircraft.

How long? A simple question that we believe deserves a simple explanation.

So is it possible for people other than pilots to estimate this time with accuracy?

Yes, absolutely.

In fact, we think you’ll be surprised at just how easy it is.

But before we give away the big “secret”, a couple caveats are necessary. First, realize you are estimating the time. As long as people drive the ambulances and fly the helicopters, there will never be exact times.

Second, if you’ve worked EMS longer than a day, you already know there are very few absolutes in our business. Variables, by definition, constantly change. Destinations can change, addresses change, patient condition can change, and so it goes. At times it seems the only constant in our business is change. Realize we are teaching an easy estimation technique. Real times can and do vary with changing variables and circumstances.

Okay, now that we’ve covered all the common sense disqualifiers, let’s get to it.

Here it is, the big “secret” that makes the math so easy:

EMS helicopters cruise at about 120 knots.

Some go a little faster, some a little slower, but all travel across the earth at about 120 knots. Don’t panic, you don’t have to do any math with 120.

Here’s the cool part:

120 knots equals about two miles per minute. Two is a simple number.

If your landing zone is 30 miles from the closest helicopter base, you now know it will take about 15 minutes for the helicopter to fly to you (30 / 2 = 15).

If you also know the launch time for your local helicopter, say ten minutes, you now know the estimated time of arrival is 15 + 10 or 25 minutes.

That’s it! ... We warned you it was easy.

Take the total straight line distance in miles the helicopter needs to fly to reach you and divide by two. Then add the launch time to that number. Simple. So easy a pilot can do it. :-)

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Troy Shaffer @
The Flight Safety Network
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