sentences:  The first JATO tests using an ERCO Ercoupe plane took place in late July 1941; though they aided propulsion, the units frequently exploded and damaged the aircraft.Parsons theorized that this was because the ammonium nitrate became dangerously combustible following overnight storage, during which temperature and consistency changes had resulted in a chemical imbalance.Parsons and Malina accordingly devised a method in which they would fill the JATOs with the fuel in the early mornings shortly before the tests, enduring sleep deprivation to do so.