Limited Performance Margins
I can’t speak to European HEMES operations but I can address what I believe may be a contributing factor to the mishap rate here in the United States. The vast majority of US HEMS operations are would fall into a category identified as a traditional model. These are typically single engine machines strategically located to provide the operator with a solid business base for the machine. The AS-350 series make up a significant portion of this fleet. The AS-350 has limited payload range when kitted out for HEMS operations. It is typical to operate very near or at the aircraft’s maximum gross weight on every mission. A 250-300 lb patient in the US is the norm today in the US. At 33% fuel burn and using 11% (20 min.) with three 180 lb crewmen the fuel load would have to be limited to 45%. This leaves the pilot with only 1 hour mission fuel. Flexibility is not the norm.
Weight (Lbs) Arm (inches) Moment (inch-Lbs)
Total Empty Weight 3383.0 136.9 463132.7
* EMS Equip. 136 190.0 38787
Pilot Equip. 40 44.2 1745.9
Aircraft Basic Weight 3558 141.6 503665.6
Pilot 180 61.0 10980
Med 1 (fwd) 180 100.0 18000
Med 2 (aft) 180 100.0 18000
Mission Ready Weight 4098 134.4 550645.6
0
Patient 250 95.0 23750
Fuel (%) 45
Fuel (gal.) 146 Max. 66 0
Fuel 440 136.8 60217.992
Weight CG Moment
Takeoff Weight 4899 129.5 634613.592
* EMS Equip. includes items listed below in green
Available Payload 51 (lbs.) HOGE Wt.
23.23 (kgs.) 4950
Baggage Comp. EMS Equipment
Para Pack (9 lbs) 10
Backboard (14.5 lbs) 0
RSI Kit (16 lbs) 16
Tri Blue Bag (11 lbs) 11
Mast Pants (10 lbs) 10
KED Kit (9.5 lbs) 9.5
Green Bag (6 lbs) 6
Vent (2 lbs) 3.5
Traction Splint (5 lbs) 5
Misc. Equip. (3 lbs) 4.5
Total 75.5
By contrast the hospital based programs operate light and medium twin engine machines that provide sufficient payload range allowing for much greater flexibility and performance margins. I hope the Wt & Bal transfer to the PPRUNE format. It does not appear as if the excel spread sheet and chart translated very well. If anyone would like a copy just send me an email.