Lighten the load of an aircraft

All aircraft have a maximum gross weight for safe operations. Weights are checked before the airplane takes off, and the pilots occupy themselves with all that is involved in flying the airplane. Sometimes something goes wrong in flight, and the plane is may be too heavy.

Allow me to tell a couple of stories to illustrate.

I have been reading about WWII bombers including the B-17 and the B-24 for some future articles for this blog. I have read some accounts of a heavily damaged bomber making her way back to base. Perhaps an engine was out and the performance of the bomber was suffering. Once they back in friendly territory and no longer at risk for being shot down in enemy territory, the pilot had to find a way to lighten the aircraft to have the best odds of returning to base. So, he would order the crew to dump equipment, armament, etc. overboard. The now lighter aircraft may be able to make it back to base. Or at least land or ditch in friendly territory.

Several months ago a commercial airliner got in trouble shortly after take-off. If memory serves, they had a hard time retracting their landing gear. They had to return to the airport, but they were too heavy to land. Procedures called for the pilots to jettison some fuel until a safe landing weight was reached. They circled at a safe altitude for something like 20 to 30 minutes. The fuel evaporates in the air, well before it reaches the ground. After the safe landing weight is reached, the pilot returns to the airport for an emergency landing. Emergency vehicles are on alert. The landing gear holds and the pilot brings the plane down safely. No injuries and fatalities. The passengers deplane and catch a later plane to their destination.

I believe that I was about three or four months into writing about aerial wildland firefighting when I first learned that all (or most) tankers and helo pilots have the capability to jettison a full load of retardant when an emergency arises. Such emergency situations where the tanker pilot will jettison a load of retardant include an engine failure, and getting caught in bad winds. Of course there are important considerations here before jettisoning the retardant because the weight of falling retardant can kill people on the ground so a tanker pilot will not make an emergency drop if there are folk on the ground in the path of the emergency drop.

I have some numbers for you to demonstrate the weight of the retardant. That will come in my next post. If the weather and the power grid allow, I hope to be making this post on Wednesday.