Friday, April 10, 2015
Evil in the Form of Electrons
The Ministab allowed hands-off flight with altitude and heading hold – by 1970 standards these were “Starwars” capabilities. Anyway, I was the first to fly a mission, so off I went in my “Starfighter” Jet Ranger. The weather was perfect and I was enjoying watching the electrons do their thing when the time came to call the ship. I grabbed the hand microphone, keyed the mike and immediately found myself pointed at the surface of the ocean, which, thankfully, was 1,000 feet below. The mike went one way, my hands the other, and in short order the ocean was back to where it was supposed to be. After a few moments of giving thanks to God for my survival, I made a command decision and shut the radio off. I know evil when I see it, and obviously that radio was evil. So I landed on the ship with no notice, which was greeted with less than enthusiasm. I didn’t care. I grabbed my passenger and returned to base. An investigation by our maintenance staff revealed that the avionics shop had installed the cable run to the antenna from the marine band radio parallel to the command wiring for the Ministab for about four feet in the overhead. I didn’t know much about the evils of Electromagnetic Interference (EMI) at that time, but like I said, I know evil when I see it.
Thirty years later, as program manager for Los Angeles County Fire’s Firehawk program, I was reviewing Air Methods Corporation’s (AMC) test flight plan for delivery of the modified Firehawks. When I got to EMI testing, I was floored by the amount of time and effort involved. But the Firehawk aircraft had been extensively modified and, in the end, I came to understand what is involved. The effort up front to shield and separate offending systems resulted in a clean test program. This in spite of the fact that AMC folks told me that the Firehawk platform was the most intense EMI platform that they had worked on at that time.
Today, because of the electronic density of the aircraft flown, I think most pilots and mechanics are at least cognizant of what EMI is and that it needs to be accounted for when modifying aircraft. That belief was put in question recently. A new helicopter was delivered to its customer and... let me stop here; if you think I am going to point any fingers here, you’re wrong. I like working in the helicopter business and it’s too small to piss off many folks. Maybe the FAA once in awhile, but not working folks. Anyway, after the helicopter was delivered it was observed that one of the major subsystems would not operate. Phone calls were made, great upset was observed and the subsystems technical reps came forth to cure the problems at hand, which is why God made tech reps. Upon much head scratching it was observed by one of the subsystems folks that when the hoist arm was extended to its operational position the problem went away. The evil doer turned out to be a hoist camera, more specifically poorly shielded cabling to the hoist camera.
My concern here was the proximity of the poorly shielded cable and the hoist cable cutter device. The hoist cable cutter uses an electrically triggered pyrotechnic charge to cut the cable in case of an emergency.
Should the completion center have caught this? Yes, but do you think that’s going to mitigate your sense of loss when one of your people in an aircraft that you program managed is injured or worse? Program managing new aircraft acquisition or modifications can be very rewarding. But attention to details beyond writing a check is why your employer put you in that position.