By lex, on March 4th, 2009
The F/A-18 is a wonderfully simple aircraft for a pilot to merely fly, a fact made possible by its hideous internal complexity. This complexity is hidden from the pilot (thank God!) by brilliant engineering. After having once heard a lecture on the flight control system, I remarked to a companion that it reminded me of the Schleswig-Holstein dispute: Only three men had ever really understood it; one had died, another had gone mad and the third had forgotten everything.
One of the main innovations in the transition from the F/A-18A to the C-model was a motive flow system – essentially an eductor that uses forced fuel flow to move more fuel from place to place. The motive flow system was slightly more complicated (but much lighter) than the mechanically operated, engine driven boost pump it had replaced. From the pilot’s perspective however, fuel just moved when it was supposed to – the internal system is entirely automated, there are no switches to throw.
But there are certain times when you don’t want the fuel to move between tanks. When you’re low on fuel anyway, and operating with an engine out, it wouldn’t make much sense to transfer fuel from the operating engine’s feed tank to the inoperative one. Automatic motive flow cut-off valves ensure that it doesn’t do so. Usually.
A military jet crash that resulted in the death of four people and the destruction of two San Diego homes was “clearly avoidable,” military officials said in a press conference Tuesday.
“The tragedy that occurred on the 8th of December was caused by mechanical malfunctions on two different engines … which presented the pilot with a complex emergency compounded by well-intended but incorrect decisions which ultimately resulted in the fuel starvation of the aircraft’s remaining engine.,” said Col. John Rupp, operations officer for the 3D Marine Aircraft Wing in San Diego.
Automation is a great good thing, because it permits one man to operate a complex piece of machinery in a high-task loading environment without having to much worry about the hardware he’s sitting on. Instead he can focus on the 100,000 tons of cold, hard steel runway lurching and rolling around like a drunken man in front of him, or navigating to a heavily defended target and employing ordnance on it with a good chance of surviving.
But automation can also breed complacency as well as encourage a shallow understanding of the underlying complexity of any given system. After all, no one man can understand it all.
Yet if the air is an unforgiving mistress, so too can be the United States Marine Corps, especially when facing intense public scrutiny over a decision revealed – in retrospect – to be a poor one:
Officials in Washington, D.C., said Tuesday that 13 Marine Corps personnel have been disciplined for errors in connection with the crash. Service officials told members of Congress that four Marine Corps officers have been relieved of duty for directing the Hornet to fly over the residential area. Nine other military personnel received lesser reprimands. Officials said the pilot should have been told to fly over San Diego Bay and land at Coronado.
Most mishaps involve many contributing elements – a chain of events, rather than a single decision. Sometimes you can line up five or six pieces of Swiss cheese and still see daylight on the other end – the holes line up.
It’s a mere eight miles between NAS North Island and MCAS Miramar. Two minutes of flying time. In this case at least, that was one and half minutes more flying time than a young Marine aviator had. Four people died, another four have lost their careers and nine have had their careers wounded. No doubt the FA-18 community is far smarter now on the fuel system of their aircraft than they were last month.
But I wonder: What else do we not understand?