Hot surface ignition of jet-A fuel by conductive deposits

Deposits found on Trans World Airlines flight 800 wreckage revealed that corrosion within the fuel tanks had produced conductive deposits. The present work has shown that these deposits are capable of causing a hot surface ignition of Jet-A vapors given sufficient electrical input. A logistic regression of ignition data showed that power was a relatively good predictor of ignition. Measured surface temperatures near the deposit exceeded the hot surface ignition temperature of Jet A. A thermal model of the process demonstrated that electrical power dissipation alone could produce the observed surface temperatures.; The ability of the deposits to dissipate electrical power and cause ignition was correlated to the number of times the deposit had been exposed to Jet A and electrical power. The deposits initially did not dissipate significant power; but as the number of exposures increased, the ability of the deposit to dissipate power and to produce local hot spots increased. This change in the electrical property of the deposit coincided with changes in the chemical makeup and structure of the deposit. The initial deposit was primarily silver oxide while deposits capable of high power dissipation were primarily carbon and silver based material.