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United States Department of Agriculture

Agricultural Research Service

Air Curtain
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AIR CURTAINS FOR THE PREVENTION OF INSECTS FROM ENTERING OR LEAVING PASSENGER AIRCRAFT

Journal of Economic Entomology 98:183-195. 2006  

This project used commercially available air curtain units to create air barriers to prevent the passage of mosquitoes and house flies on aircraft. Under NORMAL BOARDING conditions, the barrier would be used to prevent mosquitoes and house flies from entering an aircraft doorway with the passengers. Conversely, the ALTERNATE BOARDING CONCEPT deploys the air current to prevent on board insects from leaving the aircraft.

Normal Boarding

The Air Curtain technology particularly lends itself to use at those airports in which passengers board or disembark through a passenger boarding bridge. Research conducted so far shows excellent efficacy at preventing insects from entering the aircraft, as all passengers and air crew board the aircraft as normally by passing against the airflow of two commercial Air Curtains. Results showed 95 to 100% efficiency in preventing 200 laboratory-reared mosquitoes and houseflies from entering, or smaller groups of 20 mosquitoes and flies from entering with 25 simulated passengers.

(Click on images to enlarge)
  Aircraft with Air Curtains deployed View of aircraft with 6 foot tall Air Curtains deployed on either side of a real aircraft door at Orlando International Airport.   Top view of simulated aircraft Top view of simulated aircraft with Air Curtain locations in simulated boarding bridge assembly in Gainesville.  

The video below shows two Air Curtains operating in the simulated passenger boarding bridge (Jetway TM). These powerful electric-powered units are standing on one end on either side of the doorway and direct strong converging airflows into the Jetway. This is intended to prevent insects from passing through the doorway with passengers. The converging airflow is measured at 5 to 10 meters per second, which is not uncomfortable to walk through.

However, it is easy to see what happens to the red balloons, and what happens to an insect that attempts to fly through the doorway. Here, the balloons are rapidly blown 5 meters away into a net screen that is placed over a simulated aircraft doorway.

Nearly 6000 cubic feet per minute of air is generated by these 110 volt units made by Berner International, New Castle PA.

Air Curtains in action
Requires Apple QuickTime

Alternate Boarding Concept

This approach keeps insects on board the aircraft when it has just arrived and is disembarking passengers and air crew. It has Air Curtains deployed at the passenger exit, but now they blow air into the aircraft. Since the air must go somewhere, it leaves through an open aircraft door with a one-piece Net Curtain stretched tightly across it, until all passengers and crew have left the aircraft.

(click on images to enlarge)
  Dr. Dave Carlson at the aircraft exit Net Curtain deployed in a real 757 aircraft doorway   Cross section of the simulaton Cross section of our simulation showing the location of the Net Curtain and Slat Curtain. Air direction is shown by the arrows.  

The next video shows a Slat Curtain deployed in the catering door of a simulated commercial aircraft. The slats are made of weighted screen, but the weights are not adequate to hold them vertical.

Air Curtains - Alternate Boarding Concept
Requires Apple QuickTime

The airflow rapidly blows the red balloons the length of the simulated cabin and out the doorway. If the Air Curtains are powered up, we believe that any slat curtains would not be effective in preventing movement of insects, even if they were impregnated with pesticide. They will be effective only if there is no airflow through the aircraft cabin.

Caterers move 15 to 20 drink and food carts off and onto a typical 757 using a 1R or 3L doorway. The next video shows a simulated catering cart moving through a Slat Curtain deployed in a aircraft doorway. The slats should disturb and retain mosquitoes that cling to the caterer or cleaning crew. This Slat Curtain is removed and replaced by a Net Curtain before Air Curtains are powered up again for passenger boarding.

Moving carts through the Air Curtains
Requires Apple QuickTime

Protocol for Testing the Alternate Boarding Concept

This protocol is intended to eliminate or minimize spraying of pesticides on aircraft as insects are retained on board arriving aircraft by the use of Air Curtains, pesticide-impregnated Net screens and Slat Curtains. Typically Net and Slat Curtains material have 2% Permethrin (Sumitomo Chemical Co., a synthetic pyrethroid very effective against mosquitoes).

We have been exploring alternatives to chemical disinsection thus will determine the efficacy of permethrin-treated curtains deployed at service doors. Presently, we will complete laboratory tests to determine the efficacy of the permethrin-treated curtains, for which simulated catering carts will be moved in and out of the simulated aircraft. If the tests are successful, then we plan to test the system--using Air Curtains and Net Curtains--in a pilot test in Jamaica. For that test, the goal will be to prevent any mosquitoes and other flying insects from exiting the aircraft on flights arriving in Montego Bay.

To determine the efficacy in the laboratory of the treated Net Curtains, we intend to follow the protocol for determining the efficacy of the air curtain with respect to sample size and general procedures; however, caterers pushing surrogate catering carts would pass through a treated Slat Curtain rather than an Air Curtain.

The operational protocol for implementing the test at Jamaica follows in two versions--both without the spraying of d-Phenothrin and spraying of d-Phenothrin with no one on board is described below: Protocol for air curtain deployment at the door of passenger aircraft before disembarkation. The intent of the procedure is to reduce and/or eliminate the use of pesticide on board passenger aircraft.

A. Protocol for Air Curtain deployment to keep insects on board aircraft, using American Airlines 757 narrow body aircraft, 3 doors in use, pesticide-treated Net Curtains (NC) and Slat Curtains (SC), no aerosol pesticide use:

  1. Move Air Curtains (AC) onto lip of passenger boarding bridge pointed inward on either side of the passenger disembarking door (L1).
  2. Crack and open rear door of aircraft when stairs have been deployed: one air crew unrolls and installs a curved pesticide-impregnated net curtain (NC) over this door (L3).
  3. Turn on Air Curtains (AC).
  4. Disembark passengers, then air crew who pass through airflow (L1).
  5. Ground crew installs pesticide-impregnated slat curtains (SC) at rear door (L3) and/or (R1) after cracking catering doors, removes and stows NC. (Air Curtains turned off)
  6. Cleaning crew & caterers enter, service aircraft as usual then leave, R1 and L3 closed.
  7. AC turned on, new aircrew deploys Net Curtain at L3, passengers board,
  8. Passenger door (L1) and L3 closed, NC stowed.
  9. Air Curtains turned off, stowed on boarding bridge.
  10. Slat curtains (R1, L3) removed and stowed by air crew.

Note for Protocol A without aerosol pesticide: - 3rd and 4th Slat Curtains are needed if cleaning crew (L3) and caterers doors (R1) are used as at MBJ.

B. Operational Protocol for Air Curtain deployment to keep insects onboard aircraft, example used is American Airline 757 narrow body aircraft, 3 doors in use, two Net Curtains (NC), d-phenothrin aerosol pesticide used after disembarking passengers and aircrew:

  1. Move Air Curtains (AC) onto lip of passenger boarding bridge pointed inward on either side of the passenger disembarking door (L1 or L2).
  2. Crack and open rear door of aircraft when stairs have been deployed: one aircrew unrolls and installs a curved pesticide-impregnated Net Curtain over this door (L3).
  3. Turn on Air Curtains.
  4. Disembark passengers, then aircrew who pass through airflow.
  5. Turn off Air Curtains and treat aircraft with aerosol pesticide, wait for period of time X.
  6. Cleaning crew & caterer enter (L3, R1), remove/stow Net Curtains, service aircraft as usual.
  7. New aircrew, passengers board, passenger door closed.
  8. Air Curtains turned off, stowed on boarding bridge.
  9. Rear (L5) & catering door (R1) closed.

Note for Protocol 3B after aerosol pesticide treatment such as d-phenothrin: Slat Curtains are not needed, as all cabin doors (L1, L3, R1) can remain open.

We believe that the efficacy of the curved netting over a door with an airflow passing through the aircraft excludes passage of all insects. They cannot pass this material, and in any case, tend to cling to seats, people or any surface and do not tend to fly in a airflow.


Last Modified: 9/12/2006