No one is surprised when the NTSB declares that the probable cause of a midair collision is the failure of one or both of the pilots to see and avoid the other aircraft. The statement is used so often that it has become an aviation safety cliché. In its recent report on the collision of a Cirrus SR22 and a Robinson R44 II helicopter near Maryland’s Frederick Municipal Airport (KFDK), the Safety Board said it again. They also identified several contributing factors. I think they should have noted that had any one of them been missing, the accident likely wouldn’t have taken place. In other words, there were missed opportunities to prevent this accident that had nothing to do with the pilots seeing and avoiding at that time on that day.
The accident occurred on October 23, 2014, at about 3:37 p.m., EDT. The flight instructor, commercial pilot receiving instruction and passenger in the helicopter were killed. The private pilot of the Cirrus wasn’t hurt, and his passenger received minor injuries. The pilot deployed the Cirrus Airframe Parachute System (CAPS) and the airplane descended under the parachute, stopping just above the ground when it became wedged nosedown between relatively narrow-diameter tree trunks, with one tree puncturing the trailing area of the left wing just about where it meets the fuselage. The helicopter was destroyed when it hit the ground next to single-story buildings.
The NTSB said the probable cause of the accident was, “The failure of the helicopter pilots and airplane pilot to maintain an adequate visual lookout for known traffic in the traffic pattern.... Contributing to the accident was the airplane pilot’s descent below the published airplane traffic pattern altitude (TPA) and the helicopter pilot’s climb above the proper helicopter TPA as prescribed in the Federal Aviation Administration’s Aeronautical Information Manual for airports without published helicopter TPAs. Also contributing to the accident were the lack of a published helicopter TPA, the absence of radar equipment in the tower and the controller’s inadequate task prioritization.”
The NTSB needs to be respectfully reminded that to stop aircraft from running into each other, we need to know what we should be doing differently. As of the time I’m writing this, the NTSB hasn’t come out with any Safety Recommendations from this accident. There’s room for a few. Remember, the pilots weren’t the ones who refused to come up with money to install radar in the airport’s control tower. They aren’t the ones who failed to standardize a traffic pattern altitude for helicopter operations at the airport. They didn’t make controllers in the tower improvise a system to track traffic, increasing their workload and distracting them from looking out the window. While the accident would have been avoided if one of the pilots had seen and avoided the other aircraft before it was too late, I’m convinced it also would have been avoided if any of the contributing factors identified by the NTSB, and some not singled out by the agency, weren’t lined up waiting to entrap an unsuspecting pilot.
The collision took place in decent VFR conditions. About 35 minutes before the collision, the weather observation at KFDK showed scattered clouds at 4,800 feet MSL, visibility 10 miles and wind from 330 degrees at 16 knots, gusting to 21. The sun was 26 degrees above the horizon, high enough not to totally ruin your vision even if you were flying on a 225-degree heading in its direction.
The SR22 had been on an IFR flight plan from Cleveland, Tennessee. In addition to FAA radar data and air traffic control voice recordings, investigators were able to recover flight data that had been recorded by the airplane’s Primary Flight Display (PFD) system. The data showed that the airplane departed Cleveland Regional Jetport at 12:43 p.m. It cruised at about 7,000 feet MSL and maintained a heading of about 050 degrees. At about 3:19, it began a descent. The flight was being handled by a controller at the Potomac TRACON who, at about 3:25, notified the controller in the Frederick tower that the airplane was about 14 minutes west of the field for a visual approach to runway 30. At about 3:27:30, the airplane leveled off at 3,000 feet, overflew the Martinsburg VOR, and turned to a heading of about 080 degrees. At about 3:34, the flight was handed off to the Frederick tower.
The pilot radioed the KFDK controller that he was “...ten miles west at three thousand with [information] papa.” The controller instructed the pilot to “...report three miles west for a left downwind runway three zero.” The pilot acknowledged, and the controller turned her attention back to a Cessna Citation 525 pilot requesting an IFR clearance, and traffic that included one helicopter in the air, two of which wanted to get into the air, and a Cessna 182T on a practice ILS approach to runway 23. The helicopter already in the air reported on a left downwind to land on the grass. The pilot of the helicopter that would be involved in the collision radioed the controller, asking to take off from taxiway “A” and then fly a left traffic pattern and land on the grass. That was followed by another helicopter from the same operator also asking to depart for left closed traffic and a practice landing on the grass.
The controller was handling all positions in the tower. Often at Frederick, the positions of clearance delivery, ground and local are combined. The controller who she had relieved offered to stick around and help out, but she declined. Traffic hadn’t been too heavy, and she had plenty of experience in using multiple radio frequencies and juggling positions. In fact, she started out as a controller in the Air Force in 1974, worked in the tower at Newark International Airport, the New York TRACON and the Dulles airport tower, among other places.
At about 3:36:06, the controller issued an IFR clearance to the Citation crew. It took about 43 seconds. While she was listening to the Citation’s readback, the pilot of the Cirrus called on the local control frequency that he was three miles out and making a 45-degree entry for downwind to runway 30. Then, one of the helicopters radioed while the Citation pilot was still doing the readback. But, the controller heard enough and, at 3:37:10, cleared the helicopter to land on the grass, but asked that he stay at 1,000 feet on the next traffic pattern entry because she had traffic in the downwind. The helicopter pilot acknowledged.
At 3:37:23, the controller told the Cirrus pilot “...report midfield left downwind for runway three zero, I’ll have three helicopters below you in the, ah, traffic pattern.” The Cirrus pilot responded, “I have reported midfield downwind and I got two of them in sight....” The controller replied, “...I have you in sight, runway three zero, maintain your altitude until turning base, cleared to land.” Within three seconds, there was a transmission from an unidentified source. It consisted of someone screaming in the background while a male voice made excited utterances. I listened to the recording. It’s a distressing thing to hear. The Cirrus had flown into the rotor system of the R44 helicopter. The collision took place at about the point where the helicopter had turned from crosswind to downwind in the traffic pattern. The NTSB figures that the altitude was 1,100 feet MSL, lower than the traffic pattern altitude for light fixed-wing aircraft, but higher than the altitude frequently used by helicopters when in the pattern.
“While the accident would have been avoided if one of the pilots had seen and avoided the other aircraft...it also would have been avoided if any of the contributing factors identified by the NTSB, and some not singled out, weren’t lined up waiting to entrap an unsuspecting pilot.”
At 3:37:50, the pilot of one of the other helicopters reported, “...airplane down and helicopter down.” The controller responded, “Yes, yes, I saw it.” She then told the airplane doing the practice ILS to “...exit the Class Delta [airspace].”
An NTSB investigator interviewed the Cirrus pilot when he still was in the emergency room of a local hospital where he had been taken as a precaution. He said when he told the Frederick controller he could see two helicopters, one was at the 12 o’clock position in front of him and the second was at 9 o’clock some distance away. He said that as soon as he finished advising the tower, he saw the third helicopter also at his 9 o’clock position, but very close to his airplane. He said he immediately pulled back on the control stick to attempt a climb and avoid a collision. Then, he felt the impact on the left side. He said the aircraft began to dive. He almost instantaneously pulled the parachute handle.
The Cirrus was equipped with a traffic advisory system. The device transmits pulses to interrogate Mode C or Mode S transponders on other aircraft. It picks up replies, and calculates the position and distance. The system creates a visual display of nearby traffic. When an intruder gets too close for comfort, the system sounds an aural warning to alert the pilot. The aural warning is shut off when the aircraft’s flaps are deployed at the half and full settings, such as in landing. If part of the airframe of one or both aircraft blocks the signals, the system’s ability to track the target is affected. Immediately after the accident, the pilot told a state police officer that he didn’t receive a traffic alert before the collision. He repeated that assertion to the NTSB investigator. The NTSB didn’t establish the reason for the traffic alerting system not issuing an alert. It did report that the airplane’s flap switch was in the 50 percent position, but the flaps and flap actuator were up, and the actual flap position couldn’t be determined.
The control tower at Frederick is a contract tower, run by a commercial company for the FAA. Back in 2013, it was on the list of 149 contract towers that the FAA planned to close because of budget cuts known as sequestration. Some people really were bewildered by the decision to close the Frederick tower. First, it was virtually brand new, having been built with $5.3 million of federal stimulus and earmark money. Second, the Frederick airport is home to AOPA, and what kind of message would closing it send about government support of general aviation?
Although the tower was kept open, a link in the chain leading to this accident was put in place by keeping it devoid of radar. Current radar antennas don’t pick up targets in the KFDK area below about 1,100 feet, so improvements would be necessary to enable Frederick controllers to track targets down to the runways. A figure floated for the cost to put in a display of the Washington, D.C., radar was $400,000. But, the money wasn’t spent and even after this accident still hasn’t been spent. Just this past June, the airport manager was quoted in a local newspaper as saying that they might add radar sometime in the future. He added that it’s not an FAA requirement.
The tower also isn’t connected to the FAA’s Flight Data Input/Output (FUDO) system, adding to the controller workload and distractions. They have to use handwritten progress slips for IFR operations and track VFR operations on small plastic “chips” that have aircraft information written in grease pencil. The chips are placed on a wooden board called the “chip board” at the local control position. That’s the way it was at the time of the accident. Isn’t it also the way it was in the days of Super Constellations and DC-6Bs?
Frederick Municipal Airport management published a brochure that showed the single-engine and light multi-engine traffic pattern altitude as 1,300 feet MSL, the heavy multi-engine and jet pattern altitude as 1,800 feet MSL and the helicopter traffic pattern altitude as 1,100 feet MSL. These altitudes also appeared on a poster that had been put up in various places around the airport. When interviewed by an NTSB investigator, the controller who handled the accident aircraft said the helicopter traffic pattern altitude was 900 feet MSL. She said it was in the control tower’s standard operating procedures. Problem is, investigators couldn’t find it there.
The helicopter operator told an investigator that the traffic pattern altitude they use for their helicopters is between 900 feet and 1,000 feet MSL, except when they’re practicing autorotations. Then, they use 1,200 feet MSL. When asked how he came up with the 900-feet pattern altitude for his pilots and students, he replied, “It just kind of morphed into that. The airplanes are at 1,300 feet MSL, and we thought we should be below that. They never published that in the AFD, and I wish they would.”
Indeed, the FAA didn’t show any helicopter traffic pattern altitude for KFDK in its Airport/Facility Directory (AFD). Its Aeronautical Information Manual (AIM) says that when there’s no published altitude, traffic patterns for helicopters should be flown at 500 feet AGL. KFDK’s published elevation is 306 feet MSL, which would result in a helicopter traffic pattern altitude of barely over 800 feet, if you were going by the AFD and AIM at the time of the accident. After the accident, the FAA updated the AFD to show a helicopter pattern altitude of 1,106 feet MSL or 800 feet AGL at KFDK.
What was on paper and what the pilots decided to use as traffic pattern altitudes would have been of no consequence had only the controller specified pattern altitudes to be used on the downwind. She sort of did this when she told the Cirrus pilot to maintain altitude until turning base, without giving a number. But, it was too late. While it’s not an unusual omission at a busy airport, verbalizing pattern altitude assignments does help underscore where pilots need to be and makes it easier to highlight possible conflicts.
While it’s true that this accident took place when the pilots failed to see and avoid the other aircraft, I believe it’s equally true that if the other safety issues had been foreseen and avoided, the Cirrus and R44 wouldn’t have collided.
Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, visit www.ntsbreporter.us or write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.