06 nimrod mra4 natural icing trials

RAeS 4th SFTE FTSW – 28 September 2010 - UNCLASSIFIED

Knowing when to ask for help.

Nimrod MRA4 Natural Icing ProgrammeNashville TN, USA - Feb 2008

Ed Townshend- Nimrod Test & Evaluation


Scope

• Background to Trial• Trial Planning• Trial Execution• Results• The Outcome• Lessons learnt


Background – The Requirement


Background – The Requirement

ICING CLEARANCE

ICE SHAPES

FULL ENVELOPE

HANDLING

NATURAL ICING

ANTI ICE SYSTEM

PERFORMANCE

ACCRETION MODEL

BASIC HANDLING

PERFORMANCE

DRY AIR TESTS

ANTI ICE SYSTEM

PERFORMANCE


Background – Certification Requirements

PRE DEPLOYMENT

CONFIRM WEATHER

CHARACTERISATION

PROBES HAVE NO

EFFECT ON HANDLING

Def-Stan Requirements & JAA Guidance

DEMONSTRATE ICING PROTECTION

•DEMONSTRATE ICE PROTECTION ACROSS RANGE OF

ICING CONDITIONS (APPENDIX C)

•DEMONSTRATE ICE PROTECTION SYSTEM UNDER SINGLE

FAILURE STATE

•VALIDATE ENGINE AND AIRFRAME ICE PROTECTION

SYSTEM MODELSDEMONSTRATE TOLERANCE TO ICING

•CONFIRM ICE ACCRETION MODEL CORRECT

•DEMONSTRATE BASIC HANDLING & SYSTEM

PERFORMANCE UNDER FULL AND PARTIAL PROTECTION.

•CONFIRM ICE RELATED PERFORMANCE PENALTIES


Background – The Aircraft

• PA1 used as primary programme handling aircraft.• Fully instrumented Anti Ice System • No Mission System Radar, but standalone Weather radar fitted

Horizontal stabiliseranti-icing

Engine intakeAnti-icing

Wing leading edgeanti-icing

Ice detectionprobe

Visual ice accretion vane

Heated Windscreenpanels


Planning – Start point

ZERO

Pre trial Company Military aircraft icing experience:


Planning - Logic

DEFINED &

UNDERSTOOD

REQUIREMENTS

MANAGE ICE

ENCOUNTERS

IDENTIFY

RISKS

MAXIMISE

EFFICIENCY

CERTIFICATION

MINIMISE

EXPOSURE

TO RISKS

Programme Timescales Maximise Safety


Planning – Gathering experience

HOW TO MEET

CERTIFICATION

REQUIREMENTS

HOW TO CAPTURE

RESULTS

HOW TO FIND ICING

DESIGN AUTHORITY

WORKS WITH

CUSTOMER EXPERTS

CONTRACT WEATHER

CHARACTERISATION

EXPERT

CONTRACT

METEOROLOGIST

WITH ICING EXPERTISE


Planning – Finding Icing

• Identify time of year trial programme planned• Identify list of potential venues from experience• Identify factors for scoring locations and weighting:

• Daytime available

• Frequency of Icing encounters within range

• Base Weather / facilities

• Availability of diversions

• Air Traffic Density

• Quality / Availability / Cost of Forecasting data

• Nashville chosen from list of Prestwick, Keflavik, St Johns & Central USA• Extensive dialogue with FAA to build understanding with US ATC

Picture courtesy of NASA


Planning - Accurate Meteorology

• Weather out of our control• Response to weather is under our control

• In depth knowledge of icing weather systems• Maximise understanding of forecast• Target weather and plan Escape routes• Continue to monitor weather as it evolves• Track aircraft throughout flight• Compare route with forecast and results• Refine onward approach


Planning - Instrumentation

• Wing pylon with two instruments for droplet

diameter measurement and identification:• Forward Scattering Spectrometer Probe (FSSP)

• 2 Dimensional Cloud optical array probe (2DC)

• Window mounted King Probe to measure Liquid

water content

• System partially integrated into existing FTI

• Existing FTI records aircraft system performance


Planning - Instrumentation

• Four video cameras mounted in windows / pylon• Window mounted periscope with camera mount for tail observation• Multiple handheld stills and video cameras for crew use• Ice depth gauges mounted on wings and tail


Planning - Instrumented Aircraft


Planning - Informed Meteorologist


Planning - Communication

sortie plan Conduct TestEncounters feedback

Traditional Open Loop method

Remaining testing

Weather forecast Takeoff Land


Planning - Communications

THE GAP


Planning - Communication

sortie plan Conduct TestEncounters feedback

Traditional Open Loop method

Closed Loop method

Conduct Test Encounters feedback

Remaining testing

Weather forecast

Weather update / PIREPS / Aircraft LocationPIREPS – Pilot Icing REPorts

Takeoff

Takeoff

Land

LandMeteorologist

sortie plan

Remaining testing

Weather forecast


Planning - Satellite Communications


Planning – Crew roles

• 10 Crew • 2 pilots, Navigator, Comms to fly aircraft safely• 3 FTOs to monitor icing build up and anti ice system status &

performance• 1 Weather Characterisation Expert, Design Authority FTO & Customer

Representative FTO to provide on board expertise and test validation.• Second Team of 5 FTOs to enable concurrent reporting


Planning - Summary

HOW TO MEET

CERTIFICATION

REQUIREMENTS

DESIGN AUTHORITY

WORKS WITH

CUSTOMER EXPERTS

HOW TO CAPTURE

RESULTS

CONTRACT WEATHER

CHARACTERISATION

EXPERT

HOW TO FIND

ICING

CONTRACT

METEOROLOGIST WITH

ICING EXPERTISE

PLAN FOR TRACKING

WEATHER AND A/C

INSTRUMENTED

AIRCRAFT TO RECORD

WEATHER

CLEAR TEST

REQUIREMENTS AND

SUCCESS CRITERIA


Planning – Trial approval

• Two main documents required:• Flight Test Programme document • Operational Management Plan

• Trial assessed as High / Medium Risk• Concept and Safety Reviews mandated

• Required approval from the Company, UK Military

Flying Regulator, & FAA


Planning – Considered Risks• Ice accretion on unprotected surfaces not as expected• Ice accretion on protected surfaces due to poor system performance or

severe conditions• Ice induced Landing gear / flap system malfunctions• Reduced directional stability leading to increased sideslip / fin loads• Stalling with ice is new untested configuration• Engine flameout or damage due to intake ice shedding• Damage on ground due to ice shedding


Planning – Logic Summary

DEFINED &

UNDERSTOOD

REQUIREMENTS

MANAGE ICE

ENCOUNTERS

IDENTIFY

RISKS

MAXIMISE

EFFICIENCY

CERTIFICATION

MINIMISE

RISKS

Programme Timescales Maximise Safety

Combine knowledge of Specialists & Operators


Execution

• Departed UK 29th Jan – date set 1 year previously• Fitted External Instrumentation• Redeployed briefly to avoid Severe Weather• Flew 11 sorties over next 21 days • Flying only curtailed by:

• 1 day President Bush visit to storm victims

• 1 day servicing

• 1 day aircraft snag

• 6 days unsuitable weather

• Removed external instrumentation• Arrived back in UK 4th March, again within plan


Execution – Incremental Approach

Experience

Time

Full AI = Airframe + Engine Anti Ice ON

Part AI = Airframe OFF + Engine Anti Ice ON

Full AI handling - 0.5”

Dry Air Rehearsal

Part AI handling – 0.5”

Part AI handling - 1.0”



Part AI handling - 1.5”

Full AI Systems Tests - 2.0”

Appendix C completion


Execution – Area covered


Results – Wing – Protection On


Results – Wing – Protection Off


Results – Wing and Tail


Results - Fin


Results – System Failure Test


Results – Runback


Results – Probes


Results – Post flight observations


Results – Encounter Envelope

Continuous Maximum (Stratiform Clouds) CS25 Appendix C - Nimrod MRA4 Trials Data

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

10 12.5 15 17.5 20 22.5 25 27.5 30 32.5 35 37.5 40

Mean Effective Drop Diameter (Microns)

LW

C g

/m3

F132F133F134F135F136F137F138F139F140F141Series12Series4Series11Series5Series3Series2LWCAir Temp 0°C

(+32°F)

-30°C (-22°F)

-10°C (+14°F)

-20°C (-4°F)

LIQ

UID

WA

TE

R C

ON

TE

NT

MEAN DROPLET DIAMETER (Microns)


The OutcomeHOW TO MEET

CERTIFICATION

REQUIREMENTS

HOW TO CAPTURE

RESULTS

HOW TO FIND

ICING

TASK AGREED COMPLETE BY ALL PARTIES BEFORE DEPARTURE

ICE WAS FOUND AND SAFELY CHARACTERISED ON EVERY TEST FLIGHT

11 FLIGHTS

61 HOURS

21 DAYS


Lessons Learnt

• Get help for areas where you are lacking knowledge and experience

• Planned Concept of Ops worked extremely well:• Meteorologist and Weather Characterisation experts• Satellite telephone communications• Design Authority and Customer direct involvement

GO OUT AND GATHER THE BEST POOL OF EXPERIENCE TO GET THE BEST RESULTS


Questions

06 nimrod mra4 natural icing trials

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