In a wilderness emergency, few decisions carry more weight than the call to request helicopter evacuation. Call too early and you burn resources for a walk-out. Wait too long and a stable patient becomes a critical one. This framework gives you a repeatable process for making that call with confidence.
Why This Decision Is Hard
Helicopter evacuation is fast, expensive, and not always possible. Weather, terrain, daylight, and aircraft availability all work against you. The pressure to "wait and see" is real — but so is the risk of a patient deteriorating beyond the point where ground evacuation remains viable. A structured go/no-go process removes emotion from the equation.
The Four-Factor Framework
1. Patient Condition — Is this time-critical?
Go factors:
- Altered mental status that is worsening
- Respiratory distress that cannot be managed in the field
- Uncontrolled internal bleeding or signs of shock
- Spine or femur fractures with long carry-out times
- Anaphylaxis stabilized but remote from definitive care
- Diabetic emergency unresponsive to field treatment
No-go (ground evacuation acceptable):
- Isolated extremity fractures, splinted and stable
- Minor lacerations controlled with wound care
- Mild altitude illness responding to descent
- Patient ambulatory with assistance
Key question: Will this patient's condition worsen faster than a ground evacuation can get them to definitive care?
2. Terrain and Carry-Out Time — What's the realistic ground option?
Calculate your honest carry-out time. Account for:
- Number of rescuers available
- Trail grade and obstacles
- Patient's ability to assist (litter vs. walking)
- Darkness or incoming weather
General threshold: if ground evacuation exceeds 4–6 hours for a time-critical patient, helicopter evacuation is worth requesting immediately, even if availability is uncertain. Requesting doesn't commit you — it starts the clock.
3. Landing Zone Feasibility — Can a helicopter actually get to you?
Before you key up the radio, think through:
- Clearing size: minimum 100 feet × 100 feet for most rotary-wing aircraft; larger is safer
- Obstacles: trees, power lines, slope angle (ideal LZ is under 7 degrees)
- Surface: avoid loose debris that creates brownout or whiteout conditions
- Altitude: high-elevation LZs reduce lift capacity and may require a different aircraft
If no suitable LZ exists within reasonable distance, communicate that clearly when you make contact. Search and rescue teams can advise on hoist operations or short-haul alternatives.
4. Environmental Conditions — Will a helicopter actually fly?
Pilots make the final go/no-go on their end, but you need to report conditions accurately:
- Ceiling height and visibility
- Wind speed and direction at the LZ
- Precipitation and icing risk
- Time to darkness (most civilian helicopters do not fly at night)
Do not oversell conditions to get a faster response. A grounded helicopter helps no one.
Making the Call
Once you've worked through all four factors, your decision matrix looks like this:
| Patient Time-Critical? | Ground Evacuation Viable? | Action |
|---|---|---|
| Yes | No | Call immediately |
| Yes | Marginally | Call and begin ground evac simultaneously |
| No | Yes | Ground evac, monitor for changes |
| No | No | Call, but lower urgency |
When in doubt, make the call early. You can always cancel a request. You cannot undo a delay.
What to Say When You Get Through
When you reach dispatch or coordination, lead with:
- Your location (GPS coordinates if possible, landmarks as backup)
- Number of patients and chief complaints
- Patient stability — is this worsening?
- LZ description and current weather
- Your contact method and frequency
Keep it brief, factual, and calm. Rescuers need information, not narrative.
Train for This Before You Need It
The go/no-go decision is a perishable skill. If you're practicing it only when a patient is in front of you, you're practicing too late. S&S Training Solutions builds evacuation decision-making into our wilderness first aid curriculum — because the best time to think through this framework is before the emergency, not during it.
Ready to sharpen your skills? Browse our upcoming courses →