Download - Ice Crystal Icing
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws.
Copyright © 2011 Boeing. All rights reserved.
Ice Crystal Icing
Bill McKenzie, 757/767 Technical PilotBoeing Training & Flight Services
Jeanne Mason, Senior Specialist EngineerBoeing Propulsion Systems Division
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.2
“I did not fly through a Mesoscale Convective System”
Ice Crystal Icing – View From the Flight Deck
Weather radar
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.3
Agenda
• What is Ice Crystal Icing– Engine effects– Weather– Reports from the Flight Deck
• Statistics and Example Event
• Industry Activity
• Boeing Activity
• Flight Crew Inputs
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.4
Core air travels downstream to the combustor
Potential ice crystal accretion areas
Fan
Ice shed from compressor surfaces can cause engine instability such as surge, flameout, or engine damageIce shed from compressor surfaces can cause engine instability such as surge, flameout, or engine damage
What Is Ice Crystal Icing?
The physics: • Crystals can form ice on engine surfaces warmer than freezing• These warm engine surfaces are in the compressor aft of the fan
The physics: • Crystals can form ice on engine surfaces warmer than freezing• These warm engine surfaces are in the compressor aft of the fan
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.5
What is Ice Crystal Icing? (continued)
• Frozen ice crystals impinging on a warm surface in the engine• Some crystals melt, wetting the surface• Crystals impinging on wetted surface stick, cool the surface to 0°C• Ice begins to form• At high altitude, ice can form deep in the engine core
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.6
What is Ice Crystal Icing?
It can also clog probes like the Total Aircraft Temperature (TAT) probe, (some airplanes) and the engine inlet temperature probe (some engines)
TAT probe
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.7
Weather
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.8
What’s New – Ice Crystals!
• Convective clouds which cause engine power loss range from isolated CBs to tropical storms and hurricanes
• Common factors – water lifted to very high altitude
• Ice crystals form just above the freezing level to cloud top
• Ice crystal mass can be 4x the certification standard for supercooled drops for engines
• Away from the core of the storm, in the anvil, ice crystals have been measured to be very tiny –size of baking flour
Convective / Cumulonimbus cloudConvective / Cumulonimbus cloud
Supercooled water(airframe icing)
Supercooled water(airframe icing)
High concentrations of ice crystals
>50K ft>50K ft
Upwind side:supercooled liquid sometimes goes higher
Upwind side:supercooled liquid sometimes goes higher
Freezing levelFreezing level
Mixed-phase icingMixed-phase icing
Heavy RainHeavy Rain
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.9
Ice Crystals are Hard to Recognize and Avoid• 80% of all events - little or no returns at flight level• Amber and red returns below the aircraft • Low updraft velocity, light to moderate turbulence• Aircraft in deepest (tallest) part of the cloud• Clouds can spread out hundreds of miles
Freezing level
TropopauseMany engine events occur withoutflight-level weather radar returns
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.10
Hurricane Michael, K-band Radar on Instrumented Aircraft
Canada
23,000 ft.19,250 ft
11,800 ft.
Not Visible on Pilot’s Radar GR
EEN
AMBE
R
RE
D
Freezing Level
Tallest cloud region – clouds above the tropopause – directly below = amber & red on normal radar
Test aircraft flight path – image from upward and downward looking K-band radarImage courtesy of Walter Strapp, Environment Canada. Reference: Abraham, J., J. W. Strapp, C. Fogarty, and M. Wolde, 2004:Extratropical transition of hurricane Michael. Bull. Amer. Met. Soc., 85, 1323-1339.
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.11
Canada
23,000 ft.19,250 ft
11,800 ft.
Not Visible on Pilot’s Radar GR
EEN
AMBE
R
RE
D
Freezing Level
Hurricane Michael, K-band Radar on Instrumented Aircraft
Image courtesy of Walter Strapp, Environment Canada
On board weather radar would only see green ahead. At freezing level it would also see amber and red
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.12
Aggressive Down Tilt Needed to See Amber at Freezing LevelAt Cruise on a tropical ISA+15 Day, 6 degrees down-tilt needed at 40 nm
36000 ft
15000 ftFreezing level
6 degrees
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.13
Typically, clouds which cause events are about 100 nmi/185km in diameter
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
15000 16000 17000 18000 19000 20000
Time (seconds)V
ertic
al A
ccel
(g's)
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
Tem
pera
ture
(Cel
sius
)
Start End
Potential damageLight Turbulence
Moderate Turbulence
TAT Anomaly
Turbulence
Tallest cloud
region
“Satellite” Weather Analysis: A Recent Event
• Traversed 195 km/ 105 mi through tallest cloud region
• Pilots reported no radar returns at flight level
• Moderate turbulence at onset of TAT anomaly
• Engine performance shift: potential damage location
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.14
Ice Crystal Icing Reports from the Flight Deck
• Speckled green on weather radar
• Rain on the windscreen
• Small collection of ice particles on wiper post
• “Shhh” sound
• TAT near zero
• Humid cockpit
• Ozone smell
• No engine changes
Conditions “Sometimes” Reported
IMC (always) Rain effect
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.15
Statistics and Example Event
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.16
(5 engine types)
Engine Events Per Year
• GE90-94B• CF6-80C2• RB211-535E4• PW2000• JT8D/MD-80
Industry Awareness is Increasing
• Since 2003, increased: – Identification of events – Awareness and reporting
• Since 2008: – 2 new engines affected – Vibration symptom added
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.17
7 Engine Flameouts on a Single Descent
Three events involving multiple engine flameouts (7 flameouts total)
High-altitude ice crystals indicated as the cause of engine power loss
• Convective storm near Manila
• Aircraft was descending through turbulent weather
• Avoiding strong radar returns
• 26000 ft: engines 3 and 4 flamed out and recover
• 24000 ft: engines 1 and 2 flameout and recover
• 18000 ft: engines 1, 2 and 4 flameout and recover
Boeing and Engine Company Proprietary Data
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.18
Flight Data Review Recorder Data for Event 1
Aural Bank WarningAural Bank WarningMax A/P WheelMax A/P Wheel
FlameoutFlameout
Rudder InputRudder Input~18 seconds~18 seconds
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.19
Event Analysis
• To date, all large transport engines have recovered and operated at commanded thrust for remainder of the flight
• In this event, thrust asymmetry exceeded autopilot authority, requiring flight crew input, even though engines recovered
• Confusion factors included– Weather– Turbulence– Re-route / diversion– Thrust changes
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.20
Industry Activity
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.21
New Regulations ComingResearch Projects are Underway
• New regulation for ice crystals will be published in 2012
• Four areas of research underway:– Instruments for measuring ice crystal icing in the
atmosphere– Experimental data characterizing the ice crystal
environment – Research on engine ice crystal accretion and shedding– Engine test facilities representative of flight environment
This work will take time to complete before practical problem solving can begin
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.22
NASA/FAA/Boeing/Environment Canada/Airbus
Atmospheric Research Is Still Planned
• Flight program for High Ice Water Content (HIWC) Atmospheric Characterization goal: definition of convective atmosphere containing ice crystals to use as engineering standard
• Flight Program planned for 2012, 2013 – focused on the weather that produces engine events
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.23
Boeing Activity
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.24
Boeing Publication Activity
• Technical Bulletin
• Symposiums
• Aero magazine articles
• MyBoeingFleet (web site)
• Flight Crew Training Manual
• Supplementary Procedure
• QRH Checklists
Pilot Reports
and
Event Analysis
Pilot Reports
and
Event Analysis
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.25
Key Message In All Publications: Avoid
Avoid ice crystal icing weather• During flight in IMC, avoid flying
directly over significant amber or red radar returns, even if there are no returns at airplane altitude
• Use the weather radar controls to assess weather radar reflectivity below the airplane flight path. Refer to weather radar operating instructions for additional information
• Deviations of up to 50 nm may be needed to follow the guidance
• We know this is not always practicalSpecific model/engine checklist steps will be covered in the breakout sessions
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.26
Technical Bulletin
Table of Contents1. A New Threat2. Pilot Reports3. Indications of Ice Crystal Icing4. Industry Efforts5. Research6. Key Points for Flight Crews7. More Information8. Frequently Asked Questions9. Pilot Questionnaire10. Information for Dispatchers
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.27
Background Published Aero Magazine Articles
1st quarter 20104th quarter 2007
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.28
Background Information on ‘MyBoeingFleet’
Also available on CD-ROM
Events, Training and Resources\Safety Tools and Training Aids\Ice Crystals at High Altitude
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.29
Flight Crew Training Manual
Released July 2011
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.30
Supplementary Procedure (SP.16)
FCOM Volume 1
1. General description and avoidance recommendation
2. Refers to the new QRH non-normal checklist
3. Will be published at the same time as the QRH non-normal checklist
(Available at the breakouts)
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.32
New Ice Crystal Icing Checklist767 Example
First Actions: Set thrust manually, exit weather
4. Engine related steps added as needed
Condition statements are airplane dependent
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.33
Boeing Publications
All Model Tech Bulletin
April 2011
Flight Crew Training Manual
July 2011
Supplementary Procedures
2011/2012
Non-normal Checklists
(not 737)2011/2012
MyBoeingFleetJan 2011
Training Video & Articles
Flt Ops Conf.Sept 2011
Presentation
MyBoeingFleet4th qtr 2011
Additional presentations &
Articles
Published at the
same time
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.34
Project End Vision
Airline line pilots are:• Familiar with ICI phenomenon • Aware there is a non-normal checklist• Aware of the need for more event data
Airline management pilots:• Have materials available to help them
educate their line pilots
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.35
Summary
• Ice Crystal Icing Events are occurring on many engines
• Industry is working to better understand the meteorology and theengine icing phenomenon
• Boeing is focused on providing the best information to crews
• New material is being published by Boeing (Bulletins, Training, Supplementary Procedure, Checklists)
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.36
Flight Crew Input Is Needed!
• Most of what we understand is based on pilot reports and flight recorder data
• More flight crew reports of ice crystal encounters (with or without engine power loss) would be valuable to:
– Develop flight crew cues
– Validate current Boeing and industry understanding
– Better understand the process of ice crystal accretion inside engines
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.37
Flight Crew Input Is Needed!
Your pilot report will helpJeanne Mason
PO Box 3707 MC 9U-UUSeattle, WA 98124-2207
Your pilot report will helpJeanne Mason
PO Box 3707 MC 9U-UUSeattle, WA 98124-2207
Please use the questionnaire1. Fill out now
or 2. Put in flight bag
or3. Fill out the form on
‘MyBoeingFleet’
Copyright © 2011 Boeing. All rights reserved. Ice Crystal Icing_McKenzie-Mason.38
Questions?