Turbine Pilot

GPS is the lifeblood of single-pilot IFR helicopter operations

Pragmatism can sometimes cast a thick cloud over an otherwise enjoyable activity. Such was the case with helicopter pilots who liked flying in instrument meteorological conditions. It wasn't long ago that finding a civilian helicopter pilot with actual IFR time was rare. It simply wasn't practical to go through the certification process and required pilot training just to fly a helicopter from airport to airport, when an airplane could do the job faster and less expensively. Now, with GPS, the climate is changing.

GPS has allowed not only direct routing in the IFR system, but also the creation of relatively inexpensive nonprecision approaches to heliports and other off-airport landing sites. Several years ago, manufacturers anticipated this need and started designing sophisticated autopilots that would allow single-pilot IFR operations. Hospitals flying helicopters in emergency medical service (EMS) have been one of the primary benefactors of this new technology.

An example is the hospital I fly for, the Mayo Clinic in Rochester, Minnesota. Mayo was one of four test sites used by the FAA in its helicopter GPS development project. A new helipad under construction at the hospital delayed the design of the GPS approach — and when the pad was ready, the FAA's project manager, Steve Hickok, had left to form his own company, Satellite Technology Implementation. Still, the FAA eventually provided the Copter GPS 326 approach, but the minimum descent altitude (MDA) of 554 feet agl and visibility of three-quarters of a mile were considered too high by the hospital. The FAA contacted Hickok, who agreed to look over the approach. By correcting some inaccuracies in the land survey, he lowered the MDA to 434 feet agl and the visibility to one-half mile.

Nevertheless, Hickok felt that the FAA had chosen the wrong inbound approach heading. He designed a completely new approach, the Copter GPS 140, from the opposite direction and achieved an MDA of 374 feet agl. This left the hospital with two fully certified GPS approaches.

The program, Mayo One, flies the Eurocopter BK117-C1 helicopter. This model is the manufacturer's latest design and includes several improvements over the -B1, such as automatic power-sharing and a variable rotor speed system that senses air density and adjusts main rotor rpm for optimum efficiency. The system also adjusts both engines to the same power output, a chore that in most twin-engine helicopters is done by the pilot. This model uses the French-designed Arriel 1E engines, each producing 737 shaft horsepower for takeoff. Also, the gross weight was increased from 7,055 lb to 7,385 lb.

In addition to the standard dual VORs, dual communication radios, and an ADF, the helicopter is equipped with the Bendix/King EFS 40 two-tube electronic flight instrument system (EFIS), Honeywell autopilot and flight director, and Bendix/King KLN90B approach-certified GPS. The panel also has a color weather radar, Stormscope, and a Wolfsburg UHF radio.

Operating IFR in the EMS environment can cast an unconventional perspective on flying. The day for a Mayo Clinic EMS pilot starts at shift change, when the oncoming pilot gets a briefing regarding the aircraft condition and weather information from the pilot coming off duty. After doing a preflight inspection on the helicopter, the pilot uses a Pan Am Weather Systems Weathermation IV terminal to check for instrument meteorological conditions. If found, it becomes important to closely watch the weather during the entire shift — because a current weather check, determining whether an alternate airport is required, and filing an IFR flight plan must all be done in a timely manner when a flight is requested.

Although getting the helicopter airborne quickly is important, following the proper procedures and adhering to all safety practices are paramount. At Mayo we have developed several techniques for improving our response times — such as a go/no-go flow chart that the pilot uses like a checklist to ensure that every aspect of the IFR planning process is addressed. The flow chart incorporates quick-reference lists of alternate airports and the associated weather requirements for using them. We also have prefiled with our local controllers flight plans that allow us to just fill in the variable information to activate them.

Although we try to anticipate the weather as closely as possible, there are times when the unexpected happens. For example, after dropping a patient off, I was en route back to the hospital at night under IFR and expecting a visual approach to the hospital, when ATC issued me current weather for Rochester International Airport (located six miles from the hospital): 100 feet overcast and three-quarters of a mile visibility. Because the airport is on a hill about 200 feet higher than the town and the weather is generally a little better over the city, I decided to attempt the Copter 140 GPS approach to the hospital helipad.

The approach is the T-style design with several initial approach fixes to choose from. I requested LEKUH as the IAF, and ATC cleared me down to 3,000 feet until established on the approach. I reduced power, dialed the altitude into the autopilot, and loaded the approach into the GPS.

Reaching LEKUH, I slowed to the maximum final approach speed of 70 knots and dialed 2,700 feet into the autopilot. The helicopter turned towards GIHJO and began descending. On an approach like this, the KLN 90B provides automatic sequencing between waypoints with turn anticipation. Just before GIHJO the helicopter began a standard-rate turn to 138 degrees and rolled out on course towards IGTEQ, the final approach fix. I reset the autopilot for 2,100 feet and reduced power during the descent in order to maintain 70 knots. Two miles from the final approach fix my electronic horizontal situation indicator (EHSI) display turned from blue to green, confirming that RAIM (receiver autonomous integrity monitoring) was operating and that the GPS signal was sufficient for the approach, and the course sensitivity went from one nm to 0.3 nm at full needle deflection on the CDI.

While waiting to reach IGTEQ, I activated the heliport's pilot-controlled lighting and reviewed the missed approach instructions. When reaching the fix, I started down to the MDA of 1,540 feet msl. Passing through 500 feet agl, I disengaged the autopilot and started hand-flying the course. The autopilot is not approved for use below 500 feet on nonprecision approaches or 200 feet on precision approaches.

Arriving at the MDA, I could see the glow of the city in front of me, but it was not yet clear enough to descend. As I got closer it became sharper, and about one-half mile from the missed approach point I saw the heliport clearly and landed.

As useful as the IFR capability has become in getting back to the hospital, we still have to go VFR to accident sites. However, the vast majority of these on-scene flights are within about a 30-nm radius of the hospital. In this local area the pilots are comfortable launching at our program's VFR minimums of a 500-foot ceiling and one mile's visibility (800 feet and two miles at night).

Nevertheless, we will accept on-scene flights where we know we can get there VFR but, because of a deteriorating weather forecast, the return trip is questionable. While this may seem in direct violation of FAR Part 135.213, which requires an approved weather source to depart IFR, the FAA has issued Exemption 6175. It allows trained pilots to make a determination that there is one-half mile visibility during the day and one mile at night. The use of this exemption is limited to flights carrying a medical patient, and the helicopter's radar altimeter and weather radar must be operable. In addition, the IFR flight plan must include an alternate airport.

In these cases we use a cellular telephone to file a flight plan and receive a void time from ATC. Because of our Lifeguard status (a call sign emergency medical aircraft use to alert ATC that the flight needs priority handling), ATC will expedite clearances and issue generous void times.

Flying single-pilot in this environment can be complex. What makes this function safely is pilots dedicated to learning how to use the helicopter's advanced systems effectively, a skill that comes with time. To maintain high pilot comfort levels, we offer ongoing extensive training on subjects from aircraft systems to weather.

Accurate weather planning is critical to this type of IFR flying. To ensure that all the pilots maintain sharp weather planning skills, we started meeting once a month to discuss all IFR flights — including those turned down because of weather. This peer-run review meeting has become an invaluable tool for improving everyone's skills.

One of the two major weather problems is thunderstorms. The helicopter's on-board color weather radar with lightning detection system is displayed on the bottom EFIS tube and overlaid with course information. This makes it easy to determine precipitation levels and storm cell intensities with respect to current position and course line.

The other weather problem is icing: The helicopter is not certified for flight in known icing. Trying to accurately predict icing can be more of an art form. Using a solid understanding of the atmospheric conditions that can produce ice, area forecasts, and pilot reports, we make a determination of icing potential every couple of hours.

If the helicopter ever gets caught in rapidly deteriorating weather and needs to get on the ground, the autopilot's auto level feature can be used. When the autopilot is coupled to an ILS, it tracks the glideslope down to 100 feet agl. It then switches over to the radar altimeter and drops down to 50 feet agl while tracking the localizer down the runway centerline. In an emergency, this feature gives the pilot an extra option.

The work load in flying a helicopter on instruments is so high that should the autopilot fail, the pilot must declare an emergency. Because the hospital and Omniflight (the contractor that supplies the helicopter and pilots) are committed to all aspects of pilot training, each pilot is required to complete 1.5 hours of simulated IFR time per month. Omniflight typically staffs four pilots per helicopter. Because of the additional work load and training requirements, however, the hospital decided to increase the pilot staff to five.

As a pilot, flying IFR is challenging, yet very satisfying. And the hospital likes the added safety level and pilot proficiency that result from our higher standard of training. The IFR capability has increased our mission completion rate, and to the hospital that means better patient care. There are indirect benefits as well. For example, there have been flights where the pilot was able to climb to higher altitudes and take advantage of better tailwinds. This resulted in patients getting to the hospital up to 10 minutes sooner.

Most of the small towns we go to have airports with traditional instrument approaches and GPS overlays. Even so, Mayo One is currently working with Satellite Technology Implementation to design a network of GPS approaches directly to the major hospitals we serve. In the future these approaches may be upgraded to precision approaches, making point-to-point transports possible in the thickest of clouds.