7-1 Design of UAV Systems Sorties ratesc 2002 LM Corporation Lesson objective - to discuss Sortie rate analysis including … - Mission planning and preparation - Aircraft preparation and maintenance - Preflight / execution / debrief - Crew considerations Expectations - You will understand the basic elements of a sortie and be able to make sortie rate estimates

7-2 Design of UAV Systems Sorties ratesc 2002 LM Corporation Definitions Sortie (Webster’s New Collegiate Dictionary) – One mission by a single aircraft Sortie rate (The RAND Corporation*) – The number of missions one aircraft can fly in one day including time in the air and on the ground or SR = 24hours/[FT + GT] where FT = flight time  2  target distance/block speed GT = ground time = TAT + MT and TAT = turn around time  3 hours MT = maintenance time *

7-3 Design of UAV Systems Sorties ratesc 2002 LM Corporation Sortie elements Mission planning and preparation time Military - time required to plan and communicate an overall air operation and translate it into individual aircraft flight plans that everybody understands - Typically planned for days or weeks and conducted daily Civilian - time required to prepare and file a flight plan and receive a clearance - Manned aircraft can plan a simple flight and get an IFR clearance in a minimum of an hour - VFR flight preparations could be done in minutes - Unmanned aircraft may have to negotiate approvals far in advance (varies by country and region)

7-4 Design of UAV Systems Sorties ratesc 2002 LM Corporation Sortie elements Aircraft maintenance and preparation time All aircraft require servicing (fuel, oil, etc.), loading and scheduled maintenance (oil and filter change, etc) - Servicing can often be done during mission planning - Loading time varies widely - Military aircraft require special preparations to include weapons assembly and check out - Minimum “turn time” is typically minutes Unscheduled maintenance also occurs and often must be done before flights can be resumed - Flight critical items must be fixed, others can be “placarded’ and fixed later - Many operators do phase maintenance (periodic replacement) to minimize schedule disruptions

7-5 Design of UAV Systems Sorties ratesc 2002 LM Corporation Sortie elements Pre-flight, loading and system checks All aircraft require external pre-flight ground checks - From simple “walk-around” to thorough inspection - Typically takes 5 to 10 minutes All manned aircraft require loading - Includes pilot, crew and passengers - Time varies from 1 minute (pilot only) to 30 minutes Non-perishable cargo can be loaded during aircraft maintenance and preparation All aircraft require pre-start system checks - Unmanned aircraft require the most time - Minutes to hours - Manned aircraft time varies from 1 to 15 minutes

7-6 Design of UAV Systems Sorties ratesc 2002 LM Corporation Sortie elements Flying the mission…. Start/check the engine(s) - 1 to 5 minutes Get ground clearances - seconds to minutes Taxi to active runway - 2 to 15 minutes Perform pre-takeoff checks - 0 to 5 minutes Takeoff - 1 minute Climb - Seconds to 10s of minutes Cruise/ingress - function of mission distance & speed Pre-penetration refuel - 15 to 30 minutes Loiter/surveil - minutes to hours Engage in combat - 2 to 5 minutes Deliver cargo - minutes (drop) to hours (land) Post-penetration refuel - 15 to 30 minutes Cruise/egress - function of mission distance & speed Get clearances and land - 1 to 10s of minutes Post mission checks (military aircraft) - 0 to 5 minutes Taxi and shut down - 2 to 15 minutes or “Useful Work”

7-7 Design of UAV Systems Sorties ratesc 2002 LM Corporation Sortie elements Debrief - the time required to report and/or document the results of a mission Civilian debriefs focus on record keeping and incident and maintenance reports - 2 to 30 minutes Military debriefs are extensive - Everything included in civil debriefs plus … - Mission assessments - Intelligence information - Procedures - Etc. - Can take hours

7-8 Design of UAV Systems Sorties ratesc 2002 LM Corporation Crew considerations Civilian and peacetime military ground crews typically operate 8 hours per day, 5 days per week. Civilian air crews operate on flight hour basis Air transport crews are typically limited to a 14 hour duty day or 10 flight hours for reasons of safety - Duty day includes air and ground time On deployments, military air and ground crews operate 12 hours per day, 7 days per week - Crew:aircraft ratio usually > 1, e.g for fighters UAV crews (ground and flight) operate on 8 or 12 hour duty day basis Aircraft sortie rates typically are limited by crew considerations - most aircraft can fly more hours than their crews can work - including UAVs

7-9 Design of UAV Systems Sorties ratesc 2002 LM Corporation Figures of merit Civilian figures of merit (FOM) are typically expressed in terms of numbers of revenue flights per day Military figures of merit are typically expressed in terms of numbers of sorties generated per day per aircraft (strike missions) or sorties for required coverage (surveillance missions) under 2 conditions: Surge - what can be done in an “all-out” effort for short periods of time Sustained - what can be done in continuous effort over long periods of time Cost is an important part of military FOMs also

7-10 Design of UAV Systems Sorties ratesc 2002 LM Corporation Sortie rate example Above completed in advance Ground crew Mission Control Mission Planning and Preparation - min180 Intelligence update60 Flight plan60 Clearances60 Aircraft Preparation and Maintenance (parallel activity) - min180 Scheduled maintenance120 Fuel/oil and roll out30 Ground checks30 Above completed in advance Preflight - min66 Load mission22 Mission verification22 Walk around inspection and system checks22 Mission execution - min20241 Start engine11 Clearances11 Taxi55 End of runway/pre-take off checks33 Takeoff1 Climb10 Cruise out10 Loiter/surveillance180 Cruise back10 Hold for landing5 Land5 Taxi55 Shut down22 Quick turn - min15 “Thru flight” inspection and refuel15 Reports15 Sortie requirement (hr) End of runway inspection and safing 33 SR = 24/7.37 = 3.3 FT = 3.6 hrs

7-11 Design of UAV Systems Sorties ratesc 2002 LM Corporation RAND data * Therefore: SR  24hours/[1.68  FT + 6.4] TAT  3 hrs SR (previous example) = 1.9

7-13 Design of UAV Systems Sorties ratesc 2002 LM Corporation Intermission