History of Flight
On October 23, 2014, at approximately 1537 eastern daylight time, a Cirrus SR22 (N122ES) and a Robinson R44 II (N7518Q) collided in midair about 1 mile southwest of Frederick Municipal Airport (FDK), Frederick, Maryland. The airplane, operated by a private individual, departed controlled flight after the collision, its ballistic parachute system deployed, and it landed nose-down in a thicket of low trees and brush. The helicopter, operated by Advanced Helicopter Concepts, also departed controlled flight, descended vertically, and was destroyed by impact forces. The private pilot of the airplane was not injured; his passenger sustained a minor injury. The flight instructor, commercial pilot, and a passenger in the helicopter were fatally injured. Visual meteorological conditions prevailed. The airplane had filed an instrument flight rules (IFR) flight plan and departed Cleveland, Tennessee, about 1247 on a personal flight. The helicopter departed FDK about 1535 on an instructional flight; no flight plan was filed. Both flights were conducted under 14 CFR Part 91.
Witnesses on the ground observed the aircraft approach each other at the same altitude and collide. One witness reported the helicopter appeared to be in a stationary hover as the airplane closed on it, and neither aircraft changed altitude. A flight instructor from the same helicopter operator, flying a company Robinson R22, followed the accident helicopter in the traffic pattern and saw the airplane "fly through the rotor system" of the helicopter.
Radar and voice communication data from the FAA, along with controller interviews, detailed the events. At 1534:10, the airplane contacted FDK tower, about 10 miles west at 3,000 feet. The local controller (LC) instructed the pilot to report 3 miles west for a left downwind to runway 30. At 1535:02, the LC cleared the helicopter for takeoff from alpha taxiway. The LC then issued an IFR clearance to another aircraft (N612JD) from 1536:06 to 1536:49. At 1536:49, during the readback from N612JD, the airplane pilot reported being 3 miles out on a 45-degree entry for runway 30, but the LC did not hear the transmission. At 1537:22, the LC instructed the airplane to report midfield left downwind and advised of three helicopters below. At 1537:30, the pilot acknowledged and stated he had two helicopters in sight. At 1537:34, the LC cleared the airplane to land, telling him to maintain altitude until turning base. At 1537:41, cries were heard, and at 1537:49, a helicopter pilot reported both aircraft down.
The airplane pilot stated that after receiving the landing clearance, he saw a helicopter below and to the left, initiated an evasive maneuver, heard a thump, the airplane rolled right and nosed down, and he deployed the parachute.
Personnel Information
The airplane pilot held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. His most recent FAA second-class medical certificate was issued April 31, 2014, and he reported 959 total flight hours, with 804 in the accident airplane make and model.
The helicopter flight instructor held commercial pilot and flight instructor certificates with rotorcraft-helicopter and instrument helicopter ratings. His most recent FAA second-class medical certificate was issued April 31, 2014. His logbook showed 832 total flight hours, with 116 in the accident helicopter make and model.
The helicopter pilot held commercial pilot and flight instructor certificates with ratings for airplane single-engine land, multiengine land, rotorcraft-helicopter, and instrument helicopter. His most recent FAA second-class medical certificate was issued April 29, 2013, and he reported 2,850 total flight hours at that time. A logbook excerpt indicated 1,538 total helicopter hours. He stopped flying as a helicopter tour pilot in 1994, subsequently logging five or fewer helicopter flights per year, including one flight in 2012 and two each in September and October 2014.
Aircraft Information
The Cirrus SR22 was manufactured in 2006. Its most recent annual inspection was completed June 13, 2014, at 1,289.8 total aircraft hours.
The Robinson R44 II was manufactured in 2004. Its most recent 100-hour inspection was completed October 2, 2014, at 1,758 total aircraft hours.
Meteorological Information
The 1553 weather observation at FDK included scattered clouds at 4,800 feet, 10 miles visibility, and wind from 330 degrees at 16 knots gusting to 21 knots. The sun was 26 degrees above the horizon at an azimuth of 225 degrees.
Air Traffic Control
An ATC group reviewed radar data, voice recordings, controller records, and facility documents. The controllers stated traffic pattern altitudes (TPAs) at FDK were 900 feet msl for helicopters, 1,300 feet msl for small fixed-wing airplanes, and 1,800 feet msl for large fixed-wing airplanes and twins. The LC indicated the TPAs were published in the SOP and airport/facility directory (AFD). However, the ATM stated only the fixed-wing TPAs were published in the AFD; the helicopter TPA had been inadvertently omitted. No documentation of meetings establishing the 900-foot helicopter TPA could be produced. The helicopter operator stated the TPA was between 900 and 1,000 feet msl, determined informally. The published AFD at the time listed no helicopter TPA; the AIM suggests a helicopter TPA of 500 feet agl (about 800 feet msl at FDK). A city pamphlet and airport poster depicted the helicopter TPA as 1,100 feet msl. The tower SOP had no published TPAs. Following the accident, the AFD was updated on January 8, 2015, with a recommended helicopter TPA of 1,106 feet msl/800 feet agl.
Radar data from Potomac TRACON recorded the airplane track until seconds before the collision, but the helicopter was not tracked as it operated below radar coverage (floor about 1,200 feet msl).
Wreckage and Impact Information
The helicopter wreckage came to rest in a self-storage complex between two buildings, with all major components accounted for. The main wreckage was largely upright; the cockpit, cabin, fuselage, tailboom, engine, transmission, and rotors were significantly damaged. The "blue" main rotor blade was fractured near its root, with the outboard 11 feet of spar located 50 feet away. Control continuity could not be established due to numerous overload fractures.
The airplane came to rest nose-down in a dense thicket of brush and low trees. All major components were accounted for except the right wing flap, aileron, and right landing gear wheel and tire assembly, which were found between the two sites. The trailing edge of the right wing showed impact damage; the flap and aileron hinges were significantly damaged and twisted, with saw-tooth fractures consistent with overload. The cockpit flap switch handle was in the 50 percent position, but the flaps and actuator indicated a flaps-up position; power was on after ground contact, so pre-collision flap position could not be determined.
Medical and Pathological Information
Autopsies on the helicopter flight instructor and pilot, performed by the Office of the Chief Medical Examiner for the State of Maryland, listed the cause of death as "blunt impact injuries" for both. Toxicological testing by the FAA was negative for carbon monoxide, cyanide, and ethanol.
Tests and Research
The Avidyne Primary Flight Display (PFD) from the airplane recorded flight data. At 15:34:30, the airplane began descending from 3,000 feet msl at 500-1,000 fpm. The descent paused at 1,600 feet pressure altitude for about 10 seconds at 15:36:40, then continued at 700 fpm. The airplane entered a right bank of about 15 degrees 1.5 miles from the airport. At 15:37:36, at 1,045 feet pressure altitude and 100 knots indicated airspeed, a loading event occurred. Subsequently, the aircraft rolled 360 degrees right, pitched from 21 degrees nose-up to 80 degrees nose-down, and heading spun 720 degrees right. Altitude was maintained for about 3 seconds before a maximum descent rate of 5,470 fpm. The aircraft came to rest at 15:37:52 at 330 feet pressure altitude in a 75-degree nose-down, 46-degree left bank attitude.
Additional Information
The accident airplane was equipped with an L-3 Avionics SKYWATCH Traffic Advisory System (TAS), which interrogates transponders and provides visual and aural alerts. Audio alerts were inhibited at 50% and 100% flap settings. The system operated on line-of-sight; shielding could occur if an intruder aircraft's antenna was blocked. After the accident, the airplane pilot stated he did not receive a traffic alert prior to the collision.