Operators have reported cases of aircraft infestationby rodents such as mice and rats, and reptiles such assnakes and lizards, causing discomfort and alarmamongst passengers and crew, but also potentiallyconsiderable damage to the aircraft. Their presence inan aircraft can lead in extreme cases to the aircraftbeing grounded, especially when electrical wiringdamage has been discovered. Rats and mice seem tobe attracted by the odours emitted by the insulationaround the wires.

In-service experience has revealed that rodents andreptiles tend to board an aircraft through open doorsand access panels, when it is parked for a relativelylong period of time either in the hangar or on theapron, especially during the night when human activityis reduced. Also, they have been observed entering theaircraft during loading of catering trolleys and cargo.

by Gregoris DASSIOSCabin Furnishings & Payload Systems Engineer

Customer ServicesAirbus Industrie

FAST / NUMBER 27 3

U p to mid 1997, AirbusIndustrie had providedoperators with the

possibility of fumigating infestedaircraft with a methyl bromidebased chemical agent, referred to

as ‘SOXAL-PESTIGAS’ in theAircraft MaintenanceManual (AMM).

However, due tothe continuing inter-

national process ofbanning toxic fumigation

agents for civil use, andconcerns about the usage andpotential side effects of this agent,Airbus Industrie decided towithdraw it from the AMM.

Specifically, these concerns werefocused upon:

◗ Residue of methyl bromide stilltraceable in some areas in thecabin and cargo compartments upto 36 hours after aircraft aeration;

◗ Accumulation of methylbromide residues in the thermal-acoustic insulation blankets behindthe linings of the cabin and cargo;

◗ Compatibility of methyl bromidebased agents with sophisticatedaircraft electronic equipment;

◗ Existence ofchloroflourocarbons (CFC) inmethyl-bromide agents, which arerestricted in many countries bylaw, further to the Montrealprotocol.

Airbus Industrie launched aninvestigation to identify anotherfumigation agent, possessing thefollowing characteristics:

◗ Inert;

◗ Non toxic;

◗ Widely available in the world market;

◗ Low procurement cost;

◗ Easy to contain and transport;

◗ User friendly.

As a result, it has beendetermined that carbon dioxide(CO2) can fulfil the aboverequirements, where theextermination of the rodents andreptiles would be achieved bymeans of asphyxiation.

CO2 is already used in industryfor protecting food stored in holdsof ships and warehouses, and forprotecting cultivated plants. Inaddition, the use of CO2 forfumigation was of special interestsince its procurement cost is lowerthan Nitrogen (N2) and less of it isrequired.

In August 1999, Airbus Industrieconducted CO2 fumigation tests inan A319 aircraft. The test readingswere taken using probes placed indesignated areas in the cabin,cockpit, avionics and cargocompartments measuring the CO2

concentration at specified timeintervals.

NOTE: no live animals of any kindwere used in these fumigation tests.

The test results were positive,since CO2 concentration reachedapproximately 90% of the aircraftvolume, and scientifically it hasbeen shown that the lethal dose toexterminate a rodent isapproximately 60% of CO2 withexposure of about six minutes.Therefore, Airbus Industriedecided to implement CO2 and theassociated fumigation procedureinto the scheduled AMM revisionsfor each aircraft.

CO2 Fumigationprocedure

IMPORTANT: Operators are advised toconsult AMM 12-21-12 for the specificaircraft fumigation procedure. The AMMfor A319/A320/A321 was revised in May2000 to incorporate fumigation procedureby CO2 and for the A330/A340 in July2000. The revision to the AMM for theA300/A300-600/A310 family is plannedfor the first quarter of 2001.

In addition, operators are advised torefer to SIL 12-007, revision 01, issuedend of October 2000, since usefulsupplementary information is provided.

FAST / NUMBER 27

Solution=CO2

4

The fumigation procedure by CO2

is the same for all of Airbus Industrieaircraft. A locally manufacturedfilling adaptor is installed over theoutflow valve of the air-conditioningsystem and an outlet pipe installed atone of the cockpit sliding windows(see figures 1, 2 & 3 ).

When Airbus Industrie conductedthe fumigation test, an average CO2

mass flow rate of 3.6 kg/min wasselected, corresponding to almost2000 litres/min of CO2, by adjustingthe pressure to 8 bars at the CO2 sup-ply. In this case the filling time for anA319 was nearly three hours.Equipment is available, with a highermass flow rate capability that wouldallow large aircraft to be filled inapproximately the same time. Thefilling time is calculated using therequired CO2 mass specified in thetable below for each type of aircraftfuselage and the mass flow rateselected. When the specified amountof CO2 has been reached, the fillingprocess stops.

Although the cargo compartmentsare nominally sealed from the cabin,cockpit and avionics compartments,it was demonstrated during the testthat the cargo compartments are alsofilled with CO2. This will occurthrough the cargo compartment drainlines (the leakage in/out is in fact cal-ibrated for the purpose of assuringcontainment of fire extinguishant).

Usually, the CO2 gas is containedunder pressure in liquid form ofabout 150 Bars and at low tempera-tures. Heat exchangers and evapora-tors, (see photo " ), are used to elevatethe temperature of the gas prior toapproximately 15°C on entering thefuselage.

FAST / NUMBER 27 5

0

500

1000

1500

2000

2500

Amount of CO2

(kg)

A319

600kg

750kg

900kg

2300kg 2300kg

2500kg 2500kg

2000kg 2000kg

1700kg

A320 A321 A330-200

A330-300

A340-200

A340-300

A300 A300-600

A310

Apparatus:Sliding window adapter

Heat exchangers and evaporators

Figure 2

The following table shows the amount ofCO2 required for each fuselage #

Requ

ired

amou

nt o

f CO 2

per f

usel

age

Attachment barsprotected with foam

WingnutOutlet

connection

Woodenplate

Screw

Foam

Apparatus:Outflow valve adapter

Figure 1

Foam or Prot. hoseHook

Foam

WingnutConnection

to CO2 source

CO2 Fumigationprocedure (cont’d)

The CO2 enters the cabin througha locally manufactured simpleadapter that is installed over the out-flow valve. To ensure that the CO2

penetrates to the highest level in thecabin an outlet tube is fitted abovethe ceiling panel behind the cockpit,with the end placed at the highestposition in the fuselage. The otherend is taken out through a blank fit-ted in place of the sliding window inthe cockpit (see figure 3c " ). Thusas the level of CO2 rises in thecabin it forces out the ambient airthrough the tube. After the CO2 fill-ing process, the aircraft shouldremain closed for half an hour forrodent extermination and 12 hoursfor reptile extermination.

General informationUsing CO2 and

InsecticidesFumigation using CO2 is not

totally effective against insects butvery effective against rodents andreptiles. In case an operator needsto exterminate insects as well asrodents and reptiles then insecti-cide in association with fumigationshould be used. First the internalsection of the pressurised fuselagehas to be sprayed with ‘Baygon’,(Material No. 14-004 or 14-004A),and then, the CO2 fumigation pro-cedure should be performed.Insects such as ticks are almostresistant to high concentrations ofCO2 gas since they can close theirtrachea and virtually stop theirmetabolism. Other insects such ascockroaches will lay their eggsprior to dying. CO2 has no effect onthe eggs, however ‘Baygon’ iseffective against them.

In the case of reptiles, the fumi-gated aircraft has to be kept with alldoors, hatches and drain portsclosed and sealed for at least twelvehours. This is due to the fact thatreptiles hibernate when underthreat or lack of nutrition. They canreduce their heartbeat significantlyas well as their rate of breathing.

Rodents are exterminated afterbeing exposed to an environment

with 60% CO2 content for sixminutes.

The CO2 has an anaesthetic effectafter 20 seconds.

Penetration of the CO2 into thethermal-acoustic insulation blan-kets behind the cabin and cargo lin-ings, was measured at about 90%during the fumigation test.

Using ConventionalMethods

If an operator wishes to use con-ventional traps (spring loaded orwith adhesion) to catch rodents andor reptiles then the following tech-nique should be used:◗ Prior to placing the traps,remove all catering trolleys andthe waste from the trash com-pactors, (if any), from the galleys,from the lavatory waste bins andfrom any other container whichcould contain any waste.◗ Remove all soap bars and dis-pensers from the lavatories.◗ Remove all cosmetic productsfrom the lavatories.◗ Place the traps in the cabin, inthe aisles, below the seats, in thegalley and lavatory areas, in thecockpit, in the avionics bay, in thecargo holds, and in the FlightCrew Rest Compartment, LowerDeck Mobile Crew Rest compart-ment and Lower Deck Lavatories,if any of these are installed.◗ Close all aircraft doors andhatches for twelve hours with nohuman activity around the aircraft.

The main advantage of fumigat-ing an aircraft by CO2 over the useof conventional traps is that theresult is definitive in a specifiedtime frame.

IMPORTANT: Do not under anycircumstances use poisoncapsules for rodents, since theirlater removal could be easi lyomitted by cleaning personnel,leaving them to be swallowed bychild passengers.

Do not under anycircumstances use ultra-sonicanimal repellent devices insideand/or near the aircraft.

FAST / NUMBER 276

CO2 SUPPLIERAirbus Industrie encourages operators wishing to use CO2 for fumigation to use

the method described in the AMM. They should contact and use local CO2

suppliers and their associated equipment for performing the fumigation task. AirbusIndustrie performed the fumigation test in association with Linde AG. (see addressbelow) who supplied the gas and also the equipment.

FAST / NUMBER 27 7

A irbus Industrie, beingconscious of thedifficulties faced by

operators when pests board theiraircraft, and with the gradual

prohibition of toxic agents againstthem, has developed an effective,

user friendly solution for the eradication ofstowaway reptiles and rodents.

It uses products and materials that are in common use,and very simple to adapt to the aircraft.

Good hunting!

Contact person and address of supplierMr. Soenke WEIDGENLINDE AGSchnackenburgallee 2222525 Hamburg, GermanyTel: +49 40 8531 2146Fax:+49 40 8531 2125 e-mail: soenke_weidgen@linde-gas.deNote: LINDE AG has international distribution centres.

Installation of apparatusFigure 3

Sliding windowOutflow valve

Pressurizedarea

Connection to CO2 source

Think again! Conclusion

A

B C