Assessment of the effects of volcanic ash/dust clouds on aircraft safety

8/13/2019 Assessment of the effects of volcanic ash/dust clouds on aircraft safety

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AWERProcedia

Advances in Applied

Sciences00 (2013) 000-000

1st

Global Conference on Environental St!dies 2013

Assessment of the effects of volcanic ash/dust clouds

on aircraft safety

"ra#os $svoran!*% Sterian "anaila% &ctavian 'or Pleter

"epartent of Aerospace Sciences% niversit* Politenica of +!carest%1% Geor#e Poli,!% 01101-+!carest% R&.A/$A

Abstract

'e st!d* addresses te iss!e of aircraft operabilit* in volcanic d!st containated areas &ne of te ain points of tis

researc is te distinction ic so!ld be ade in air traffic ana#eent (A'.) and operational ters beteen volcanic

as (particles beteen 11 and 2) and volcanic d!st (particles !nder 11 or 2 4)% d!e to teir

differentiated ipact of air traffic 5orecastin# si!lation tests ave been perfored in order to assess te dispersion and

propa#ation of te volcanic asd!st particles d!rin# several real events (E*6af6alla678!ll% April 20109 P!e!*e% :!ne 2011)

We ave also anal*,ed te beavio!r of te containant in te cob!stion caber and first sta#es of te t!rbo6et en#ine

t!rbine 'e ost acc!rate and close to te act!al val!es representation of concentrations is a nocast (forecast for ';0)

#enerated b* a tested E!lerian dispersion odel it data assiilation 'e researc tea developed a post-processin#application in relation it a dispersion si!lation code tat co!ld be !sed in case of volcanic er!ption b* an* national

a!torit* or air traffic operator in order to assess aircraft safet*

2013 Acadeic World Ed!cation ? Researc Center All ri#ts reserved

1.Introduction'e E*6af6alla volcanic er!ption in April-.a* 2010 is a #ood e@aple of an event en te econoic

ris8 potential developed into eav* losses to te civil aviation co!nit* olcanic asd!st

containation is addressed differentl* in civil aviation fro t!nderstor clo!ds and all oter

eater penoena '!nderstor clo!ds aead of te aircraft a* be seen and avoided !sin# te

Airborne Weater Radar Boever% volcanic asd!st does not provide radar eco !nder noral

circ!stances Anoter concern is te e@tent of te volcanic asclo!d containation areas 'e* are

*A""RESS 5&R C&RRESP&/"E/CE= "ra#os $svoran!%"ept of Aerospace Sci% 5ac of Aerospace En#% niv Politenica of +!carest% 1%Geor#e Poli,!% sect1% +!carest% 01101% R&.A/$A

E-mail address= ddisvoran!#ailco 'el= ;D0-30-0D-0D


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Dragos Isvoranu et al. / AWERProcedia Advences in Applied Sciences (20!" 000-000

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at least one order of a#nit!de lar#er tan noral clo!d forations '!s% te decision a8in#

process to find a s!itable avoidin# ro!te b* te cre onl* is nearl* ipossible E@ternal ide-area

forecasts are reF!ired to ta8e te best decision 'ere are tree separate t*pes of treats to aviation

safet* in connection it te volcanic activit*= (PE) olcanic p*roclastic er!ption% (AC) olcanic as

clo!d% and ("C) olcanic d!st containation9 separate ris8 assessent% inforation processin#%

anal*sis in te decision a8in# process% and lines of action are appropriate for eac of tese tree

t*pes of ris8s9 i@in# or failin# to de-co!ple te tree t*pes of treats a* lead to econoic ris8(e@cessive eas!res and !n6!stified losses for civil aviation sta8eolders) olcanic d!st containation

and sand aerosols are siilar treats to aviation9 tis fact is !sef!l beca!se sand aerosols

containations are !c ore freF!ent and fairl* !s!al 5orecasted concentrations are needed for

te fli#t operations and for A'.-related decisions and not act!al (istorical) concentrations $5R

fli#t operations and air traffic ana#eent decisions need inforation an* o!rs in advance% and

te containation is rapidl* can#in#% d!e to te inds ic ove te d!st aro!nd Reliable

forecasted concentrations are deliverable !sin# a odern tande dispersion odel (E!lerian and

a#ran#ian) it dail* relevant data assiilation of act!al (istoric) concentrations% eas!red

s*steaticall*% folloin# a predeterined scee

2. Methods and techniques of determining the concentration of volcanic ash'o avoid a dan#ero!s area reF!ires Hseein# itI first 'e best e@aple of on board reote sensin#

device in !se toda* is te eater radar (AWR) and it o!ld be #reat if te AWR co!ld be !sed for

volcanic asd!st clo!ds or containation sensin#% b!t te nat!re of te tar#et (t*pical si,e of te

#rain) and te red!ced concentration tat !st be circ!vented a8e it !seless 'is brin#s !s to

$"AR (i#t "etection and Ran#in#) As an atosperic probin# device% te instr!ent is ore e@otic

tan eater radar and is not in idespread !se% e@cept for scientific researc and environental

onitorin# An iportant advanceent in $"AR as te reco#nition tat te spectra of te detected

radiation contained i#l* specific inforation related to te particle si,e% sape and coposition%

ic co!ld be !sed to deterine te nat!re of te tar#et 5or volcanic d!st containation te best

fit is an elastic bac8scatterin# $"AR also 8non as a .ie $"AR Anoter possibilit* is !sin# te S!npotoeter an instr!ent ic% en pointed directl* at te S!n% eas!res te intensit* of te

S!nJs li#t as seen fro te Eart atospere 'e f!ndaental F!antit* is te intensit* of te solar

radiation at different avelen#ts Particle si,e distrib!tion is related to te spectral dependence of

te aerosol optical tic8ness 'e ain liitation of te potoeter is dependence on direct optical

pat to te S!n and conseF!entl* on eater 'o avoid eater restriction and to cover lar#e area in

sort tie an airborne $"AR is te best option 'e obilit* is a bi# advanta#e en Hnear real tieI

eval!ation of te volcanic d!st containation is reF!ired Calibration of particle si,e distrib!tion can

be done ile fl*in# over 8non potoeters locations (#ro!nd eater station) or in collaboration

it a obile S!n potoeter

'e concentration of volcanic asd!st is te ain paraeter of te containation proble 'ere

are a n!ber of in-sit! eas!reent tecniF!es alread* deplo*ed b* te fl*in# laboratories ("R%

/R% < .et office% .KtKo 5rance) A relevant device is te E5AR% developed b* a consorti!

coordinated b* te niversit* of .ancester L1M Boever% it appears to be a proble of

eas!reent tecniF!e% ic is not ell covered in te literat!re .oreover% bot reote and in-

sit! sensin#% are basicall* line eas!reents% tat is te* deterine te containant concentration

alon# te si#t direction ic co!ld prove irrelevant ta8in# into acco!nt te si,e of te penoenon

'e proble it s!c in-sit! probes is te icroscopic scale te* eas!re concentration An ori#inal

idea o!r researc #ro!p is prootin# is te !se of an in-sit! eas!reent device naed HAirborne in-


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sit! ectoetric concentration eas!reent !nitI $ts desi#n is aied at #aterin# containant fro

a lar#e vol!e of air !sin# an electrical copressor% t!s avera#in# concentration eas!reents 'e

eas!reent noise is t!s filtered o!t nat!rall*% and te !ncertaint* of te concentration

eas!reent is inii,ed Ac8noled#in# tat S!lp!r "io@ide eission accopan*in# an* volcanic

er!ption is ver* ell correlated it olcanic As"!st concentrations L2M% researcers advanced an

indirect etod based on S&2 as a pro@* Considerin# ps*colo#ical and c!lt!ral aspects specific to

te aviation co!nit*% an indirect eas!reent tecniF!e for a treat to te fli#t safet* is not anacceptable ris8 $n tis case% direct asd!st eas!reent tecniF!es based on strai#tforard

principles are reF!ired

3. Turbine engines vulnerability to high concentration volcanic ash/dustolcanic asd!st is not detectable it on-board instr!ents% and te presence of volcanic

asd!st in dan#ero!s concentrations represents a treat to aircraft $n absence of s!itable on-board

sensors% te aps it forecasted concentrations are te onl* actionable instr!ents available to

pilots% dispatcers% air navi#ation service providers% and national aviation a!torities 'ese are

reF!ired ore o!rs in advance fro te oent of te enco!nter A pra#atic approac to te

eval!ation of o daa#in# is te f!nctionin# of a t!rbine en#ine in volcanic asd!st containatedatospere as presented in L3M Rolls Ro*ce allos operators to fl* in 2N10

O3#

3volcanic asd!st

concentration% no atter o an* o!rs% for all teir ran#e of prod!cts L3M Rolls Ro*ce and all oter

en#ine an!fact!rers aintains oever te preca!tionar* recoendation= do not fl* in visible as

'e ost catastropic dan#er is te blades profile alteration d!e to as adesion eiter fro last

sta#es of te copressor or first sta#es of te t!rbine% leadin# to increased r!#osit* or #roin#

deposits As previo!s aircraft as enco!nters prove% one of te ost si#nificant s*pto in tis case is

i#er t!rbine inlet teperat!re and of co!rse i#er EG' 'e strate#* of fl*in# in ,ones it as

concentration less tan 2#3accredited b* Rolls-Ro*ce apparentl* loo8s not so safe in te li#t of

te odern and f!t!re trends in b!rners developent Alto!# tese concl!sions are based on a lot

of e@periental or8 done b* "!nn and co-a!tors LDM at Calspan% tere are ne developents in te

atter of !sin# volcanic as vers!s sand in t!rbine in#estion tests $n te ori#inal "!nns tests it asson tat belo 2000Q5 (103QC) te saples of volcanic as did not soften to a #lass* state and

passed tro!# te en#ine% ence did not deposit on blades Recent e@periental data of Ciarelli

and co-a!tors LM reports tat% dependin# on as coposition% sinterin# for E*6af6alla as be#!n

beteen 0 and 00QC and total eltin# at 100QC

'est fli#ts of 2010 in as containated areas alon# it n!ero!s oter reports soed no si#ns

at all of as deposits% pittin# or an* oter daa#es .ost li8el* tat tese fli#t ere perfored in

areas of lo as containation% probabl* !nder 20#3 At first #lance% it sees F!ite p!,,lin#%

ta8en into acco!nt o!r above anal*sis% tat no trace of as as reported at toro!# inspections of

en#ines Corroboratin# te e@periental evidence it as in#estion tests perfored b* "!nn et al

LDM it sees pla!sible tat as concentration pla*s a a6or role Bence% e reco#ni,e te e@istence of

a tresold above ic as d!st in#estion becoes dan#ero!s 'e ecanis tat e s!spect is

a##re#ation of elted or softened as particles in te cob!stor leadin# to te observed assive

deposits on BP no,,le vane% in6ectors and so on +eneat tis tresold% as particles are so rarefied

tat te* do not coalesce Even if as elts in te cob!stor priar* ,one and% in te first instant%

solidifies on vario!s colder s!rfaces% it disappears !nder te action of vario!s ecanical vibrations

and dra# forces 'e e@planation resides in te scarcit* of te area of aderence d!e to i#

s!perficial tension forces and te brittle caracteristic of te #lass* deposit Peraps% it is ort

entionin# tat #lass repellent special coatin# of iportant passa#es of te core flo (last sta#es of


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BPC% first sta#es of BP'% etc) i#t provide f!rter c!re Red!cin# te teperat!re at te t!rbine

inlet% represents an iportant a* of event!all* reovin# te as deposits i#t ad been fored $n

o!r opinion tere is a lar#e difference beteen te effects of as and d!st on en#ine operation 'e

Calspan e@perients LDM !sed as it #rain si,e over 200 icrons collected fro te preises of

volcanic er!ption ic a* e@plain te s!bstantial daa#es reported /obod*% to o!r best

8noled#e% as ever !sed volcanic d!st !nder 3 icrons #rain si,e to assess te beavio!r of te

en#ine

. Im!act of contamination on the Air Traffic Management5orecasted concentrations are needed ell in advance ('O12% 'O1) to plan lon# ran#e $5R Ti#ts

and for traffic flo ana#eent p!rposes $nstead of act!al concentrations% te a!tors recoend

te !se of te ord eas!red 'ere co!ld be a lar#e discrepanc* beteen act!al and eas!red

concentrations% dependin# on te etod of eas!reent% b!t te act!al val!es are not available

All 8non eas!reent tecniF!es are indirect etods% s!b6ect to lar#e deviations 'ese

sortcoin#s of te eas!reent etods are less li8el* to be p!t forard b* te entities ic tr*

to develop or sell te instr!ents% b!t scientific anal*sis ill easil* reveal te Calibration probles

and lar#e acc!rac* ar#ins ill accopan* te attepts to eas!re volcanic asd!st concentrationsin a consistent and idel* available anner

'e ost acc!rate and close to te act!al val!es representation of concentrations is a nocast

(forecast for ';0) #enerated b* a tested E!lerian dispersion odel it data assiilation

'e ost relevant and operationall* eanin#f!l representation of concentrations is a forecast (';3%

';% ';% ';12% ';1% ';1) #enerated b* te above odel in 3"

". #stimated distribution of volcanic ash !articles concentration for Air Traffic by com!uterSeveral n!erical si!lations (5i# 1 a-d) ave been perfored it te freel* donloadable code

5A3"-2 $n order to attain #reater acc!rac*% te ori#inal so!rce code as been odified to accept

eteo and topo#rap* database files it resol!tion of 0 de#rees and ne eteo variables li8e

planetar* bo!ndar* la*er &n te oter and% e ana#ed to assiilate te code on Windos based

platfors $n order to provide a reliable alert s*ste it is andator* to ave an estiation beteen

te si!lated forecast and post-er!ption e@periental data ($"AR% potoetr*% etc) 'e first step in

order to prod!ce a reliable cop!tation is !p-datin# te eteo data base it nocast inforation

/e softare pac8a#e can be devised in order to assiilate te e@periental data in te #lobal

fraeor8 of te si!lation code 'is pac8a#e co!ld perfor a variational data assiilation siilar

tose e@istent in te eteo forecast codes $ts p!rpose is to prod!ce an acc!rate ia#e of te state of

te er!ption cobinin# observations it a odelled state (bac8#ro!nd forecast or first #!ess) $n

partic!lar% te 3"-ar al#orit perfors te anal*sis of tree-diensional aerosol fields% b*

inii,in# a cost-f!nction it variational etods

A ore ard!o!s proced!re involves bac8-trac8in# of te concentration field based on locall* or

folloin#-pat altit!de concentration profiles 'e idea is to odif* te a6or paraeters of te

er!ption so!rce (ass flo rate% ei#t above vent% etc) in order to atc te eas!red

concentration profiles


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a) b)

c) d)

5i#!re 1 a)-b) Snapsots of E*6af6alla er!ption of 1D-1 April 20109 c)-d) Snapsots of P!e!*e

er!ption 3- :!ne 2011 +lac8 areas reflect as concentration over D #3

'e researc tea developed te application ASBD" as a post-processor for 5AD" o!tp!t% icco!ld be !sed in case of volcanic er!ption b* an* national a!torit* or operator 'is application is

capable of te folloin# f!nctions=

iportin# forecastnocast files it D" concentrations of volcanic asd!st interpolatin# tro!# te aps in D" (location% tie and vertical coordinate)9 !sin# 5AD" to e@trapolate or forecast ore da*s in advance (inp!t of so!rce volcanic er!ption

data is reF!ired)9

e@port containation aps and vario!s #rapical forats9 calc!late and e@port artificial satellite ia#es read* to be copared to te real satellite ia#es for

an open-loop validation of te odel9

s!peripose concentration eas!reents and pilot reports to te aps% in D" (space;tie)9 s!peripose fli#t D" tra6ectories andor fli#t plans on aps9 s!peripose airports% navi#ation aids% navi#ation points% aira*s% 5$R and sector bo!ndaries

'e ASBD" postprocessor as ritten in .atWor8s .atlab and is r!nnin# on Windos UP or

Windos acines


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5i#!re 2 'e fli#t (#reen dot) alon# its fli#t trac8 is overlaid on te concentration ap

$. %onclusions$n o!r opinion% fl*in# in d!st containated areas belo D #

3is safe 'is concl!sion as been

clearl* proven b* Airb!s A320 fli#t in +ariloce% Ar#entina% !nder alost 30#3d!st concentration

on 021D2012 Recent tests LM confired tat no ear occ!rs belo a certain level of contact load

'is is o e can e@plain tat fl*ind in d!st leaves no eas!rable effects bot on te e@terior of te

aircraft and in te en#ine Since 2010% operators ave been active in increasin# teir sare of

responsibilit* and a!torit* in te decision a8in# process eter to fl* or not into containated

airspace R!nnin# a series of si!lations in a traffic scenario in an airspace containated b* an

!ncertain concentration of volcanic asd!st% te or8load of te air traffic control increased

s!bstantiall*% and *et tere as no real safet* treat detected Si!lations ere ade in te E*6af6allascenario% in te /ore#ian airspace% April 2010% !sin# te softare presented above (5i# 2)

&eferences

L1M +re#!ier% : $provin# te Acc!rac* of Particle .ass Concentration Prediction essons learned

fro te E*6af6alla6o8!ll crisis and oter cases% International Air Sa#et$ % &limate &'ange I&AS&&

&on#erence% Colo#ne% - Septeber 2010

L2M Sc!ann% olcanic As and Saaran "!st oads derived fro Airborne &bservations%

International Air Sa#et$ % &limate &'ange I&AS&& &on#erence% Colo#ne - Septeber% 2010

L3M abo!rne% " E$a#allao)ull *'e impact o# volcanic as' on aircra#t engines% $nternational Air

Safet* ? Cliate Can#e $CASCC Conference% Colo#ne - Septeber 2010LDM "!nn% .G% +aran% A: and .iatec% : &peration of Gas '!rbine En#ines in olcanic As Clo!ds%

AS+E ,ournal o# Engineering #or as *urines and Poer 1% ol 11% pp 2D-31

LM Ciarelli% C%

Documents

Assessment of the effects of volcanic ash/dust clouds on aircraft safety