 Now, let us look at a situation when the airship has exceeded the pressure of altitude and then it starts descending. So this is the operational issue, there is no numerical calculation here. Just observe carefully and try to understand the physics behind what is happening. So you have reached the maximum achieved altitude and now you are descending. As you descend, the balloon will start collecting air, why? Because they have to maintain the super pressure, otherwise you will exceed super pressure. So as you start going down from that particular condition, you will reach an altitude earlier. So the net static lift will remain constant at the new reduced value because of the loss of lifting gas. So what has happened now is you have lost lifting gas, therefore you are going to lose some lifting capacity. The lifting capacity comes minimum lifting gas. So you are coming down after exceeding the pressure height, so you do not have enough lifting gas, you have thrown it away to be able to go to that height. As you come down slowly, the balloon starts getting filled up. So as I said, what will happen is that the balloon will become full during descent. Before hitting the ground, the balloon will become full, so now you are stuck up in the air. You cannot come down further because to come down further, you need to have more air in the balloon, but balloon has no space, house full, so you cannot come down. So this is the inflation fraction, the new condition. So one can show that this can lead to a very critical situation. Now if the balloonates become full during descent, the envelope is unable to take in more air, so super pressure will be exceeded. Now without super pressure, the envelope will not be able to maintain its shape. You need super pressure because you want to maintain the shape. When it flies, there is some dynamic pressure to overcome that the pressure inside should be more than outside. So you need some super pressure but now your balloon is full even before you are reaching in the ground. So the shape of the airship will not remain the shape that it was designed for. So what you do is to avoid this situation, what you do now is, now you rupture the balloon. So you have an air to helium rip panels. So the pilot will rip the panel that can or the pulling the rip cord allows balloon air to flow in the lifting gas. So the balloon is now tight, it cannot get filled up. If you go further down, it is going to create stress in the balloon. So that will rupture, instead of that you rupture it intentionally. So now what will happen, air from the balloon will go inside the gas chamber. So you are actually corrupting the lifting gas, you are going to reduce the purity of lifting gas. So the envelope then continues to take in the balloon air and maintain super pressure but it contaminates the envelope. So when you come down, you will find that your lifting gas is not now fully pure or as pure as before because some air from balloon has now been made to go inside. So when you come down, after that you will have to purify and remove this air. It is a very costly process and you have to ground the air ship for some time. But there is no option available. So the net static lift will not change because that does not depend upon the pressure altitude. The net static lift you are now below the pressure altitude. So as much as you come down, the balloon air will be taken in. And now the balloon air is going in and going inside the envelope. So effectively speaking, the envelope is now available for the balloon air to fill therefore the shape will be maintained.