Sunday, November 10, 2013

What if?

Dennis was excited.

This was going to be his first ever patient-loaded instrument flight in the beautiful helicopter he had recently been hired to fly. As his base had just stepped up to instrument-flight-rules (IFR) capability, everyone was still learning - but he felt confident in his ability to get the aircraft, crew, and patient to their destination under IFR as the sole pilot. He had just completed an IFR flight from his base in Charleston to this little hospital in Sumter, using the precision lateral and vertical guidance provided by the instrument-landing-system  (ILS) at Shaw Air Force Base, conveniently situated near the hospital. After breaking out of the clouds on the glide slope, he had cancelled his instrument clearance and proceeded under visual-flight-rules (VFR- able to see out the windows) the short distance to the hospital. With the only IFR helicopter in the region, Dennis understood that business was going to pick up when weather conditions went down and prevented the VFR helicopters in the area from flying.

The medical crew was down in the hospital picking up the patient, a 54 year old man who needed to go the heart hospital in Columbia to have his pipes cleaned. Years of a fat-rich southern diet had slathered deposits all over his heart's supply tubes; the ones that, in a healthy person allow a flow of blood to provide oxygen and energy to the heart's muscle tissues.

The flight-assignment was ready-made for an IFR-capable helicopter. While the ceiling was low at 800 feet above the ground;, underneath visibility was excellent at more than six miles. The temperature was sixty degrees Fahrenheit, so icing would not be a factor at the planned altitude of 4000 feet. The atmosphere was stable, with no convective activity observed or forecast. Winds aloft would not create turbulence, and none was forecast.

Dennis' training had been typical for his industry. His employer had a training program that met with Federal Aviation Administration (FAA) requirements, while not being extraordinarily expensive. The HEMS industry is relatively low-paying, and has high turnover, so a large part of any operator's budget is spent on initial training. Training first focuses on operating a "normal" aircraft in visual conditions both day and night, then deals with emergency situations and aircraft malfunctions. Once the new pilot has mastered the aircraft and can deal with malfunctions, he or she is given some time to gain operating experience and learn on-the-job. After six months or so; if the program operates under IFR, the new pilot's instrument-flight training takes place. Pilots are taught how to plan and prepare for flight under Instrument Meteorological Conditions (IMC) in a time-compressed situation. Steps that might take a few hours are distilled down to what can be accomplished in about fifteen minutes, allowing a launch within twenty-five or thirty.

The "E" in "HEMS" is for Emergency. The clock is ticking.

A laminated flow-chart is often used as a checklist to make sure that no planning-steps gets missed, like fuel required, primary and alternate destination-weather requirements versus current and forecast conditions; and notices-to-airmen about the condition of the departure, destination, and alternate airports and their instrument landing equipment. Plan complete, the pilot normally calls a flight service station and files the proposed flight plan. With the plan on file, the next step is determining how the actual clearance from Air Traffic Control will be obtained. If the location allows communication with ATC by radio, that method can be used. If not, a clearance to enter controlled airspace under IFR can be obtained over the phone, which means ATC saves the airspace around the departure location for the exclusive IFR use of  the departing aircraft until it can be picked up on radar, positively identified, and have any needed changes to routing or altitude transmitted and received. Because phone clearances tie up vast sections of airspace, their life is limited, with a "clearance-void" if not off (the departure airport or heliport) within ten minutes or so.

Dennis' crew walked up the ramp, and with the help of the hospital's security guard, they loaded the patient into the back of the aircraft. Dennis stood back and made sure that the doors were closed correctly, verified that no seat-belts or straps were hanging out, checked the latches all the way around the aircraft, he even dropped down and looked underneath for leaks or anything amiss. Then he strapped in, his mind miles ahead of the aircraft. He knew that, like marriage, IFR is easier to get into than out of. An aircraft departing visual conditions for flight in the clouds goes from being able to see out the window and what's coming to being "blind." Once in the clouds, a transition back to visual conditions often requires a descent, and places the aircraft near hard things like towers, buildings, terrain, and even other aircraft flying visually and not under air traffic control. While going into the clouds can occur almost anywhere, getting out of them safely is a different story.

Dennis started both engines of the aircraft, and performed the functional checks of the autopilot and other systems. He notified his communications center that he was preparing to depart, and would be talking to and flight-following with ATC;  and that for the duration of the flight the medical crew would handle com-center calls. Because Shaw is so close to the hospital, Dennis was able to call the tower directly and announce his intentions to take off. He asked for his clearance over the radio, holding his pencil over his knee-board upon which was a sheet of paper with the letters C R A F T printed down the left margin, as the mnemonic for "clearance limit, route of flight, altitude enroute, frequency for departure, and transponder squawk code."

"ATC clears Medevac helicopter November 12345 to Columbia Downtown airport via direct. Climb and maintain 2000 feet, expect 4000 feet 10 minutes after departure. Departure frequency will be 1 2 5 point 4. Squawk six five six two. On departure maintain heading 135 degrees to stay clear of the Shaw final approach course,   Shaw winds are 180 degrees at six knots, altimeter two nine eight six. Take-off will be pilot's own risk; area not visible from the tower.  Shaw using runway two two right..."

Dennis read back his clearance, once again verified that the aircraft's systems were normal, checked that the crew and patient were ready, and asked for help, "okay guys clear me all the way around and overhead and here we go."

Once airborne and turned to 135 degrees, Dennis pulled in power for a 1000 foot-per-minute climb at 100 knots airspeed. He had preset the heading and vertical-speed bugs, and when he coupled the autopilot to the flight controls he relaxed his grip but didn't let go completely until making sure that everything was going to work correctly. He felt a gentle movement through the aircraft as the system took over and then moved his hands away from the cyclic and collective, and set his feet on the floor. He had pre-selected 2000 feet as the level-off altitude, and knew that when the aircraft reached that altitude and stopped climbing,  it would accelerate to somewhere between 120 and 130 knots, which was just the speed he was looking for. They flew into the base of the clouds at 1000 feet on the pressure altimeter, so he made a mental note of the fact that the bases were around 800 feet above the ground, in case he had to come back, glancing at the radar altimeter to make sure all the numbers fit.

"Medevac copter 345 - Shaw tower - contact departure, good day sir."

"345, wilco."

Dennis had preset the departure frequency in the radio so all he had to do was press the flip-flop button and he was on the correct freq. He listened for a second to make sure the channel was clear, then transmitted,
"Shaw departure control, this is Medevac 'copter 12345, climbing through one thousand three hundred for two thousand. Heading 135 degrees."

"Medevac 345, Shaw departure; good morning. Climb and maintain four thousand, proceed on course direct Columbia Owens."

Dennis adjusted the target altitude to 4000 feet, and pressed the direct-to button on the Garmin, noted the new course to be flown, then considered whether to use the heading-bug to turn the aircraft or the NAV feature of the autopilot. It was at this instant that disaster struck.

Turbine engines produce incredible amounts of power from relatively small packages, by super-efficiently turning jet fuel into heat-energy. As part of this process, components rotate at extremely high rates, sometimes exceeding 60,000 revolutions per minute. A tremendous amount of heat, as much as nine times the boiling point of water, or  900 degrees centigrade, must be handled by lubrication systems and cooling airflow. As long as oil and air flow as designed, the engine screams contentedly and the rotors keep turning. Interrupt the flow of air or oil however, and a turbine won't go. It was ironic that the patient on this flight had a heart with small channels that were blocked; because the number two engine had the same sort of problem. Only the engine's blockage, caused by the repeated super-heating of lubrication oil and the residue left behind by a phenomenon called coking, wasn't starving a muscle of oxygen - it was starving a bearing of oil. As the lower oil line became more and more clogged over time, the amount of oil flowing to the bearing decreased. It was Dennis' bad luck that the instant when the lack of oil flow caused the bearing to overheat and seize - with a tremendous BANG - occurred when they were in the clouds.

An "occluded" oil line - coking, discovered prior to failure.

A coked bearing... discovered prior to failure.
Photo credit: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2745290

While Dennis' training had prepared him to deal with an engine failure in visual conditions - when he could see the ground and where he needed to go, at no time had he been trained by his employer to deal with such an emergency while in the clouds. The terms "land as soon as possible" and "land immediately" take on a new flavor when one is in the clouds - and it tastes like copper on the tongue.

This is a shortcoming of the training provided to many EMS helicopter pilots flying under instrument flight rules in instrument conditions. Emergency procedures - like losing an engine (or both), or control of the fenestron, or a hydraulic boost system - are covered in class and practiced in a traffic pattern at an airport. This is part of the "VFR" training that all pilots receive. If we fly a helicopter IFR in IMC, we need to keep in mind that any of the malfunctions we prepare for in VFR conditions can happen to us while IMC. And we need to have a plan.

A simulator would be the best and safest way to prepare for this. Barring that, scenarios talked out while sitting in the aircraft, putting hands on the switches and knobs and controls that would actually be moved is better than ignoring the possibility that a problem might occur.

But what about Dennis?

He's cool.

The motor that seized blew up when it tried to stop turning from umptity-thousand RPMs all-at-once. The physics weren't right. Pieces of the motor flew off into the atmosphere, right through the engine-compartment cowlings and the rotor system.  Other pieces went right through the engine compartment fire-wall and fragged the good motor, which failed too. Dennis pushed down on the collective with gongs and bells and lights everywhere. And reverted back to his training.

"SHIT... HOLY SHIT!"  Both generators stopped making power, but the aircraft battery powered the panel and allowed him to keep flying by reference to his instruments. He checked the attitude, heading, airspeed -70 knots! 70 knots! -, and finally found the rotor RPM. It was above normal in the yellow range. "Screw it - leave it there," he thought, " I'd rather it be high than low."

The aircraft was making strange noises as it descended - quickly - but it was still flying - and he was still flying it.

"Shaw! 345! Mayday Mayday Mayday! We've lost both engines and are coming down - where's the airport?"

The voice of calm, "345 --- rrrroger,  I've got you sir - you are three quarters of a mile from the approach end of 4 left or 4 right - the airport is directly north of you now. Winds are 180 degrees at 4 knots, you are cleared to land."

"Okay guys, let's get the O's off, okay, the engines are not coming back;" his voice strained as he reached across to cut off fuel to each engine and blew the fire extinguisher bottles, "okay where are we? Okay 70 knots, rotors a little high, okay aircraft's in trim, somebody call the com-center for an ambulance (the medic had been talking to the com-center in one continuous stream of transmission since the first bang) - okay fly north, okay we can do this..."

The autorotation was different than Dennis was used to, he was on instruments instead of looking outside, and it occurred to him that this was a first-ever event. His brain was firing synaptic-contacts at light-speed, and he was thinking well ahead of the aircraft - as in "in a few seconds I am going to have to," as opposed to watching events happen to him."

They fell out of the belly of the clouds with the airport right where it was supposed to be. "YEAH BABY!" Dennis yelled. "Okay guys, seats, belts, doors, sterile cockpit!" When scared, we revert to our training. "We're ready in back!" Indeed the crew had never been so ready for a landing in their life.

Luck is a bitch. And then sometimes she isn't. Dennis rolled his eyes one last time across the instruments, thinking how strange it was to be flying with so many warning and caution lights lit up.

"Okay, we can do this, okay speed's good, okay we've got the runway, okay two hundred, okay one hundred, decel! fifty, okay here's some collective, hold her off, hold her off, level her up, okay cushion cushion cushion."

Dennis had no idea he was doing it, but he was speaking the exact same words that his instructor had spoken to him over and over during his flight training years before. And just as it had worked then, it worked now. The aircraft dropped smoothly onto the asphalt and slid down the runway, making a loud grinding sound that - truth be told - scared the new flight nurse worse than anything that had yet happened.

A fire truck pulled up alongside the right door - water cannon pointed right at them...

Our training should prepare us for real-world situations. Often it doesn't - it meets a requirement or checks a box. In the first Gulf War, I came under attack by missiles while flying from KKMC to Rafha at night under goggles. We fired flares in self-defense. The thought that went through my mind, as I waited for impact, was that I had never in my life seen a flare launched from an aircraft while wearing goggles. As a topic of discussion for your crew, consider how well  your training program prepares you for the different adverse situations you might encounter.

safe flights...

Update: to hear the audio record of a pilot having a dual engine failure click here

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