1. Approved for Public Release: NG16-1008, 6/8/16
Implications of UAV Endurance on Effective Time on Station (ETOS) and Cost per ETOS Hour
26-29 July, 2016
Tom Collipi
Technical Fellow
Northrop Grumman Aerospace Systems
Approved for Public Release: NG , 6/8/16

2. Agenda ETOS Defined Tool Overview Scenario Baseline Results
Mission Duration Trade Space
Mission Duration Trade Study Results
Excursion  Modification of Pre- and Post-Flight Time
Conclusions
Note: Notional Aircraft Reliability, Maintainability, Supportability
and Cost Data Used To Illustrate Our Methodology
Approved for Public Release: NG , 6/8/16

3. Approved for Public Release: NG16-1008, 6/8/16
ETOS Definition
Source: Venn Diagram inspired by Chris Marchefsky of NAVAIR
Effective Time On Station (ETOS) is the percentage of planned calendar time that an aircraft is actually on station and effective
Approved for Public Release: NG , 6/8/16

4. ETOS Calculation Technique
Post- flt
& Maint.
Pre-flt
Ingress
Egress
Asset 1 1 2
Coverage 4 5
Ready 1 2
Coverage 4 5
Asset 2 1 2
Coverage
Ready 4 5 1 2
Coverage
Asset 3
Ready 1 2
Cov. 4 5
Failure
Coverage
Coverage*
Cov. X
Total Time
* Coverage Requires:
Operational Aircraft
Operational Ground Station
Fully Manned Ground Station
T=0
Post-flt & Maintenance
Egress
Pre-flt 1
Ingress
Coverage* (3) 4 2 5
ETOS is Calculated In Accordance With NGC Patent No: US 7,436,295 B2 5
Approved for Public Release: NG , 6/8/16

5. Approved for Public Release: NG16-1008, 6/8/16
Tool Overview: Model for Aircraft Availability Forecasting (MAAF) 6
Approved for Public Release: NG , 6/8/16

6. Model For Asset Availability Forecasting (MAAF)
An Object-oriented, Simulation Modeling Application Intended To Help Designers, Analysts And Planners Conduct Rapid Analyses Of A Variety Of Logistics Problems, Including:
Predicting Weapon System Availability Under Various Operational Scenarios
Allocating Logistics Resources Based On Mission Requirements
Impact Of Maintenance And Operational Policies On Aircraft Availability And Resources
Assessment Of R&M Improvements On Weapon System Availability And Logistics Resource Requirements
Sizing Units, Readiness Spares Packages (RSPs), Etc.
Analyzing The Impact Of Force Structure Changes
Impact of Primary Aircraft Inventory vs. Backup Aircraft Inventory
Approved for Public Release: NG , 6/8/16

7. MAAF Object Oriented Framework
MESL*
Missions
Required Repair Resources
LOCATION
A/C 1
GS 1
EQUIPMENT
A location may possess
PLATFORMS
PEOPLE
FACILITIES
Spares SE
Operations
Maintenance
that include
Hangars
Ramps
Crew Chiefs
Avionics
Aircrews
MAAF Supports the Rapid Configuration of Scenarios to
Simultaneously Assess Mission and Support Requirements
* Minimum Essential Subsystem List
Approved for Public Release: NG , 6/8/16

8. MAAF Modeling and Simulation Construct
Direct Support
NRE Costs
Quantity & Type of
Missions
Quantity & Type of Bases.
Quantity & Type of Platforms
Quantity & Type of Support Resources
NRE and Sustainment Costs
Cost
Data
Direct Support
Recurring Costs
Fleet Ops
(SGR, Sch Eff.)
CAPE (CAIG) O&S Costs
Aircraft Hvy Maint.
Operational Requirements
Availability (Mat. Avail, MC Rate)
Sch. Maint.
Scheduled
Maint (O/H)
Supply Support
Utilization
O&S Data Output (Excel)
LSA
(Eagle)
Task Analysis (Excel)
Model for Asset
Availability Forecasting
Manpower
Utilization
SE & Facilities
Utilization
Reliability Predictions
(Relex, Excel)
R&M Input (Excel)
Support System Definition
R&M (from Simulation)
R&M Output (Excel)
Spares Analysis (VMETRIC)
Spares / Consum. Input (Excel)
Repair / Supply Depots
Levels of Maint.
Facility Capability
Cost Data
Approved for Public Release: NG , 6/8/16

9. Typical Platform MESL – Repair Actions Data
Approved for Public Release: NG , 6/8/16

10. Approved for Public Release: NG16-1008, 6/8/16
Aircraft Daily Status
Daily MC Rate
Aircraft Status
(In Heavy
Maintenance)
MAAF Calculates Availability By Tail Number On A Minute by Minute / Day by Day Basis
Approved for Public Release: NG , 6/8/16

11. Output Example: Summary Page
Operational & Availability Performance
Maintenance And Supply Job Summary
Cost of Sustaining Performance
Operations & Support Costs
Approved for Public Release: NG , 6/8/16

12. Approved for Public Release: NG16-1008, 6/8/16
Scenario 31
Approved for Public Release: NG , 6/8/16

13. Scenario: 90 Day 24/7 Persistent Surveillance Coverage
Note: Notional Aircraft Reliability, Maintainability, Supportability
and Cost Data Used To Illustrate the Methodology
2 Aircraft Models Analyzed
Gawker R&M attributes:
Mean Time Between Failure (MTBF): FH
Mean Time Between Critical Failure (MTBCF): 30 FH
Mean Time To Repair (MTTR): Hrs
Gawker Mod1 R&M attributes:
Mean Time Between Failure (MTBF): FH
Mean Time Between Critical Failure (MTBCF): 60 FH
Mean Time To Repair (MTTR): Hrs
Single Forward Operating Location (FOL) with 1 to 5 aircraft
Orbit 1 hour from FOL
2 hour pre-flight and 2 hour post-flight turn around inspections
Aircraft have 24 hour mission endurance
422 Line Items
875 Total Items
Note: Aircraft Attrition Not Considered (100% of Aborts Return to Base)
Approved for Public Release: NG , 6/8/16

14. Approved for Public Release: NG16-1008, 6/8/16
Baseline Results 33
Approved for Public Release: NG , 6/8/16

15. Approved for Public Release: NG16-1008, 6/8/16
Baseline Results
Gawker
30 Hr MTBCF
Gawker Mod1
60 Hr MTBCF
# of Aircraft:
ETOS:
$/ETOS: 1
66.84%
$7,037.30
70.28%
$6,788.38 2
88.34%
$6,709.49
93.02%
$6,493.70 3
90.61%
$7,018.49
95.17%
$6,768.29 4
90.73%
$7,420.84
95.3%
$7,091.28 5
90.674%
$7,761.0
95.3%
$7,487.85
Approved for Public Release: NG , 6/8/16

16. Baseline Results (Continued)
3 Aircraft Provides Most Effective ETOS Coverage
Approved for Public Release: NG , 6/8/16

17. Baseline Results (Continued)
Unit Level Manpower Largest Contributor to Cost As Aircraft Quantity Increase
Approved for Public Release: NG , 6/8/16

18. Approved for Public Release: NG16-1008, 6/8/16
Mission Duration Trade Space 37
Approved for Public Release: NG , 6/8/16

19. Modeling and Simulation Trade Space
Number of Platforms (A/C, UAV, GS)
Number of Locations
Operational
Dials
Mission Schedule / Priority
Duty Day / Personnel Limitations
Maximum Sortie Duration (6 to 24hrs)
Time to Orbit (1 to 3 hrs)
System Utilization
Support
Resources
Initial
Investment
Costs
Results:
Operational Performance
ETOS
RAM-C Metrics:
Material Availability
Operational Availability
Ownership Costs
MAAF Simulation
Sustainment
Dials
Reliability
Maintainability
Support Concept
Number of Personnel
Manpower Productivity
Phase / Sch Maint. Cycle
Range & Depth of Spares
Number & Type of Facilities
Component Reorder Time
Depot Throughput for Repairs
Range & Depth of Support Equipment
Reparable Equipment Turnaround Time
Sustainment Costs
$/FH or $/Yr
Cost
Knobs
Public/ Private Work Share
Supplier Work Share
Labor Rates
Overhead / Fee Structure
O&S Parametric Values
Sustainment
Dials
Approved for Public Release: NG , 6/8/16

20. Mission Duration Trade Space
3 Aircraft Deployment
Maximum Sortie Duration: varied from 6 to 24 hours
Sortie duration drives probability of abort
Sortie duration drives requirement to launch replacement aircraft
Time to Orbit: varied from 1 to 3 hours
Time to Orbit drives time on station
Approved for Public Release: NG , 6/8/16

21. Approved for Public Release: NG16-1008, 6/8/16
Mission Duration Trade Study Results 42
Approved for Public Release: NG , 6/8/16

22. 1 Hour Time To Station
8 Hour Duration (6 Hours on Station) is Knee of The Curve:
ETOS Falls Off After That Point
Approved for Public Release: NG , 6/8/16

23. 1 Hour Time To Station (Continued)
Longer Mission Duration Results in Lower Cost per ETOS Hour
Approved for Public Release: NG , 6/8/16

24. Time To Station Implications
Longer Time To Station Results In More Flight Hours and Less ETOS
Approved for Public Release: NG , 6/8/16

25. Time To Station vs. $/ETOS
Longer Time To Station Results in Higher Cost per ETOS Hour
Approved for Public Release: NG , 6/8/16

26. Approved for Public Release: NG16-1008, 6/8/16
Excursion  Modification of Pre- and Post-Flight Time 47
Approved for Public Release: NG , 6/8/16

27. Excursion  Modification of Pre- and Post-Flight Time
When an aircraft aborts, the ability to launch a replacement aircraft is driven by:
Availability of ready aircraft
Time to Pre-flight the aircraft
An excursion was performed to assess the impact of reducing preflight time (while maintaining same total mission processing task time)
Alternatives
4 hr preflight 0 hr post flight
3 hr preflight 1hr post flight
2 hr preflight 2 hr post flight Baseline
1 hr preflight 3 hr post flight
0 hr preflight 4 hr post flight
Assumptions
3 Gawker Aircraft (30 hour MTBCF)
1 hour to station
Approved for Public Release: NG , 6/8/16

28. Excursion Results Shorter Preflight Results in Significantly More ETOS
Shorter Preflight Results in More Flight Hours
Approved for Public Release: NG , 6/8/16

29. Excursion Results (Continued)
Shorter Preflight Results in Reduced Cost per ETOS Hour
Approved for Public Release: NG , 6/8/16

30. Excursion Results (Continued)
Solid Line = 30hr MTBCF
Dotted Line = 60hr MTBCF
Decrease Pre-Flight vs.
Increase Reliability
Decrease Pre-Flight vs.
Increase Duration
More Cost Efficient To Reduce Pre-Flight Time Than to:
Increase Sortie Duration or
Increase MTBCF
Approved for Public Release: NG , 6/8/16

31. Pre-Flight Time Phenomenology
Key Assumptions:
Aircraft Ready to begin Pre-Flight
1 Hour to Station
Pre-Flight Time Includes Ground Checkout and Mission Load Time Which Could Make “0” Hour Pre-Flight Time Impossible to Achieve
Approved for Public Release: NG , 6/8/16

32. Approved for Public Release: NG16-1008, 6/8/16
Conclusions 53
Approved for Public Release: NG , 6/8/16

33. Approved for Public Release: NG16-1008, 6/8/16
Conclusions
Effective Time On Station (ETOS)Tenets:
Higher Reliability Results in Higher ETOS
Longer Endurance
Tends to increase ETOS
Results in Lower Cost per ETOS Hour
Longer Time to Station Results in
More Flight Hours
Lower ETOS
Higher Cost per ETOS Hour
Shorter Pre-Flight Time Results in
Significantly More ETOS
Reduced Cost per ETOS Hour
Obvious Findings: Higher Reliability, Longer Endurance & Shorter Time Station Better
Surprising Finding: Shorter Pre-Flight Time Significantly Increases ETOS
Approved for Public Release: NG , 6/8/16

34. Conclusions (Continued)
During System Development
Care should be taken to establish the Design Reference Mission (DRM)
Foundation for the analytical assessment of Spec requirements
Usually turn around time is specified
Not generally broken out between Pre- Flight and Post Flight times
Mission planning / ground station preparation is a Pre-Flight driver for current UAVs
Once Fielded
Prior to deployment, modeling should be performed to optimize ETOS performance
Resources to be deployed
Time to station
Nominal Sortie Duration
More Cost Efficient To Reduce Pre-Flight Time Than to:
Increase Sortie Duration or
Increase MTBCF
Approved for Public Release: NG , 6/8/16

35. Approved for Public Release: NG16-1008, 6/8/16
Questions? 56
Approved for Public Release: NG , 6/8/16

37. Gawker Parametric Cost Data
Return
Approved for Public Release: NG , 6/8/16