While taxiing, the flight crew discussed deicing procedures. For waiting aircraft, equipment is used to spray special deicing fluids on the wings. The airport's drainage system overflowed, resulting in deicing fluid leaking into the river. Ground deicing of aircraft is commonly performed in both commercial and general aviation. As a deicing agent, it is much more effective at lower temperatures than sodium chloride. It is also used as an additive in airplane deicing solutions. Applications under investigation include lightning-strike protection, deicing, and structural health monitoring for aircraft. Recipients include high-lift devices, tailplane trim, deicing, galley lift (elevator) and interior services. Thickeners are also used to help the deicing agent adhere to the airplane body. New constant speed propellers and deicing boots were installed as well during 1940. This is a particular concern in regions with freeze-thaw cycles requiring frequent deicing. Investigators also found that the deicing procedures at LaGuardia were substandard. The report on the crash in Dryden criticised approaches to deicing. They found that the airport was using only Type I deicing fluid, not Type II. Investigators also focused on deicing practices at LaGuardia.