The Perfect MATCH

The instrument approach to a hover is something few rotary wing operators train to do. Although instrument training can be tedious, monotonous, and tiresome (at least for swimmers and flight mechanics), crew proficiency effecting instrument approaches to a hover provides tremendous capability and significantly improves safety margins. Like many of the skills most critical to success in challenging situations, pilots stationed at fair weather units can train for years in between employing these skills operationally.  

Over the course of my career, for each operational instrument approach to the water I have performed, I have trained the procedures dozens of times and every time I began a descent to the water with no visual cues during a mission, I did not regret all the time and sustained effort training those procedures.  

On one case alone, my crew flew four MATCHs to affect a rescue in dense fog, at night, with only a couple hundred yards of visibility. Often, during these types of events, it is clear which pilots have done the work and which pilots could have benefitted from additional preparation.  

I will revisit some of the points discussed earlier to review the steps in flying the “Perfect MATCH” to a zero-groundspeed hover: 

1. When VNV becomes active, collective is decreased to a power setting that captures the appropriate rate of descent as airspeed is maintained. 

2. When THOV becomes active, collective is decreased further to maintain rate of descent as pitch is increased to initiate a deceleration.  

3. Shortly after the initial THOV transition, the lowest power setting is reached. 

4. As the helicopter slows on the backside of the power curve, power is increased slowly. 

5. If the aircraft is slightly high, power is paused. As the helicopter slows, rate of descent increases, the aircraft descends on to glideslope, then power increases resume. 

6. As the hover bars become active, left wing down is required to avoid a right drift due to the helicopter’s translating tendency.  

7. As the CDI is replaced by hover bars, pilots monitor the magenta cross for lateral course deviation. 

8. As the helicopter nears a hover, the rate of power application increases. 

9. As the helicopter reaches the appropriate ground speed, the nose is lowered to a hover attitude, and power reaches the highest setting on the approach (slightly above OGE power to stop the descent).  

10. Power is decreased slightly to OGE power and hover attitude is adjusted slightly in pitch and roll to achieve the desired groundspeed in a hover.  

If pilots are flying a three-degree glidepath to a zero-groundspeed hover, rate of descent is roughly equal to 350 fpm at 70 kts groundspeed, 300 fpm at 60 kts groundspeed, 200 fpm at 40 kts groundspeed, 150 fpm at 30 kts groundspeed, 100 fpm at 20 kts groundspeed, 50 fpm at 10 kts groundspeed.