AndEngine, attaching 2 of the same entity affecting collision - object

Question

I am creating a game similar to Glider PRO. In the game, you control a paper airplane and you use air vents to keep you from falling on the floor. When the airplane collides with the air vent, (using collidesWith method) it pushes the airplane up. Now here is the problem, when I attach 2 air vents to the scene, only the first attached air vent works. The second one doesn't seem to collide with the airplane. I use the onManagedUpdate method in each air vent to check for the collision. This is my first time coding with AndEngine so any help on this will be greatly appreciated.
Here is the AirVent code:
public class AirVent extends Rectangle
{
private Sprite sprite;
private Glider glider;
public AirVent(float pX, float pY, float pWidth, float pHeight,
VertexBufferObjectManager pVertexBufferObjectManager,
ITextureRegion pITextureRegion)
{
super(pX, pY, pWidth, pHeight, pVertexBufferObjectManager);
sprite = new Sprite(0, 0, pITextureRegion, pVertexBufferObjectManager);
sprite.setSize(pWidth, pWidth / 2);
sprite.setPosition((pWidth / 2) - (sprite.getWidth() / 2), pHeight
- sprite.getHeight());
this.attachChild(sprite);
this.setAlpha(0);
}
public Sprite getSprite()
{
return sprite;
}
public void checkCollision()
{
if (glider.collidesWith(this))
{
glider.setGravity(glider.getConstantGravity() * -1f);
}
else
{
glider.setGravity(glider.getConstantGravity());
}
}
public void applyGliderInteraction(Glider glider)
{
this.glider = glider;
}
#Override
public void onManagedUpdate(float secondsElapsed)
{
this.checkCollision();
super.onManagedUpdate(secondsElapsed);
}
}
And the MainActivity code part:
#Override
protected Scene onCreateScene()
{
// TODO Auto-generated method stub
// 1 - Create new scene
final Scene scene = new Scene();
Sprite backgroundSprite = new Sprite(0, 0, this.mBackground, getVertexBufferObjectManager());
scene.attachChild(backgroundSprite);
roomChanger = new RoomChanger(0, 0, screenWidth, screenHeight, getVertexBufferObjectManager(), scene);
// 2 - Create the player
player1 = new Glider(339, 174, this.mPlayerGlider1, getVertexBufferObjectManager())
{
#Override
public void onManagedUpdate(float secondsElapsed)
{
if (player1.getLife() == 0)
{
// Execute your actions.
finish();
}
super.onManagedUpdate(secondsElapsed);
}
};
scene.attachChild(player1);
airVent = new AirVent(200, 100, 100, 400, getVertexBufferObjectManager(), this.mAirVent);
airVent.applyGliderInteraction(player1);
airVent2 = new AirVent(500, 100, 100, 400, getVertexBufferObjectManager(), this.mAirVent);
airVent2.applyGliderInteraction(player1);
scene.attachChild(airVent);
scene.attachChild(airVent2);
createControllers();
return scene;
}

Answer 1

I found the problem. The checkCollison() method works, but when I add a second AirVent, the if/else statements battle each other. Removing the else statement from the checkCollision() method fixed the issue but right now, that is not the way I want my game to behave.