Narrative:

In 12/88 I was PIC of a military helicopter on a training flight which originated from weide army airfield. The helicopter was equipped with a single ultra hi frequency radio and a single FM radio. My observer was sitting in the copilot's seat. Weide army airfield is located approximately 20 mi northeast of baltimore, md. After departing weide army airfield, we proceeded to the area around frederick, md, and thereafter to the carroll county airport, where we did several apches to a full stop. From carroll county airport we proceeded eastbound toward weide army airfield. After arriving in the area of weide army airfield at approximately XA20, we decided to make a couple of approachs at baltimore airpark, an uncontrolled airport approximately 5 mi south of weide army airfield. We passed over the airport at approximately 1000' above pattern altitude to determine the wind and the active runway. At this time neither my observer nor I observed any fixed wing traffic. We determined that the active runway was 27 and entered the traffic pattern. We made 1 approach to runway 27 using a standard pattern and a final of approximately 3/4 mi. I did not make position announcements on unicom or CTAF because the aircraft lacked a VHF radio. The second approach was to be a steep approach (ie, 12 degrees or more) and use the same pattern as the previous approach. I initiated a descent from the pattern altitude of 1200' MSL to an altitude of 800' MSL on base leg. In order to make a steep approach I held the altitude of 800' MSL until we were approximately 1/4 mi from the approach end of runway 27. After holding that altitude too long, I was closer to the runway than anticipated, and so I initiated a very quick descent by lowering the collective full down. This produced a high rate of descent (note that there is no vsi in the helicopter to determine the rate of descent). Approximately 50' from the runway I initiated a deceleration maneuver while I was increasing the power and rotor pitch by pulling up on the collective. A deceleration maneuver was required by my high rate of descent. The aircraft stabilized approximately 15' above the runway and from this point a very slow, precise landing was made. After landing onrwy 27 I had spoken a couple of sentences to my observer and was increasing the power by raising the collective when both my observer and I heard the sound of an aircraft engine. We both looked toward the sound which was to our left and observed a fixed wing aircraft, small aircraft Y, approximately 60' latitude from our position and 20' above the runway. The small aircraft Y was in a 30 degree left bank and executing a go around. Thereafter, while still at very low altitude, the small aircraft Y quickly entered a 30 degree right bank, crossed the centerline of runway 27 and continued climbing to the northwest. We lost sight of the aircraft. We departed runway 27 and continued looking for the fixed wing aircraft. On crosswind we still had not made visibility contact with the aircraft. Just after turning from crosswind to downwind we made visibility contact with the aircraft. The aircraft was at our 7 O'clock position coming towards us at a high rate of speed. Thereafter, we lost sight of the aircraft as it entered our 6 O'clock position and reappeared at our 4-5 O'clock position, approximately 1/2 mi behind the aircraft. The small aircraft Y continued to accelerate and positioned his aircraft at our 3 O'clock position approximately 50-60' latitude. The small aircraft Y continued to fly at our 3 O'clock position for approximately 30-60 seconds. He then accelerated to our 1-2 O'clock position approximately 2000' in front of our aircraft. He then made a 90 degree left turn which passed directly in front of our aircraft and crossed perpendicular to our downwind flight path approximately 2000' in front of our aircraft. The small aircraft Y then descended to approximately 600' MSL on crosswind, and flew at that altitude down runway 27. Then the aircraft turned crosswind, downwind and base at the same altitude and finally landed on runway 27. Thereafter, the aircraft taxied over to one of the hangars and parked. This incident arose because of 2 primary factors. The first factor is that the military equips many of their aircraft with only UHF radios. These aircraft are operated in the civilian ATC system where the primary radio is VHF. At uncontrolled airports this prevents the military aircraft from receiving position announcement from civilian aircraft over the unicom or CTAF. The second factor in this matter is that a fixed wing aircraft took advantage of a landing aircraft and misjudged distances between the 2 aircraft in violation of the FARS.

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Original NASA ASRS Text

Title: NMAC BETWEEN MIL-HELICOPTER AND GA-SMA WHEN MIL MADE STEEP APCH TO RWY.

Narrative: IN 12/88 I WAS PIC OF A MIL HELI ON A TRNING FLT WHICH ORIGINATED FROM WEIDE ARMY AIRFIELD. THE HELI WAS EQUIPPED WITH A SINGLE ULTRA HI FREQ RADIO AND A SINGLE FM RADIO. MY OBSERVER WAS SITTING IN THE COPLT'S SEAT. WEIDE ARMY AIRFIELD IS LOCATED APPROX 20 MI NE OF BALTIMORE, MD. AFTER DEPARTING WEIDE ARMY AIRFIELD, WE PROCEEDED TO THE AREA AROUND FREDERICK, MD, AND THEREAFTER TO THE CARROLL COUNTY ARPT, WHERE WE DID SEVERAL APCHES TO A FULL STOP. FROM CARROLL COUNTY ARPT WE PROCEEDED EBND TOWARD WEIDE ARMY AIRFIELD. AFTER ARRIVING IN THE AREA OF WEIDE ARMY AIRFIELD AT APPROX XA20, WE DECIDED TO MAKE A COUPLE OF APCHS AT BALTIMORE AIRPARK, AN UNCONTROLLED ARPT APPROX 5 MI S OF WEIDE ARMY AIRFIELD. WE PASSED OVER THE ARPT AT APPROX 1000' ABOVE PATTERN ALT TO DETERMINE THE WIND AND THE ACTIVE RWY. AT THIS TIME NEITHER MY OBSERVER NOR I OBSERVED ANY FIXED WING TFC. WE DETERMINED THAT THE ACTIVE RWY WAS 27 AND ENTERED THE TFC PATTERN. WE MADE 1 APCH TO RWY 27 USING A STANDARD PATTERN AND A FINAL OF APPROX 3/4 MI. I DID NOT MAKE POS ANNOUNCEMENTS ON UNICOM OR CTAF BECAUSE THE ACFT LACKED A VHF RADIO. THE SECOND APCH WAS TO BE A STEEP APCH (IE, 12 DEGS OR MORE) AND USE THE SAME PATTERN AS THE PREVIOUS APCH. I INITIATED A DSCNT FROM THE PATTERN ALT OF 1200' MSL TO AN ALT OF 800' MSL ON BASE LEG. IN ORDER TO MAKE A STEEP APCH I HELD THE ALT OF 800' MSL UNTIL WE WERE APPROX 1/4 MI FROM THE APCH END OF RWY 27. AFTER HOLDING THAT ALT TOO LONG, I WAS CLOSER TO THE RWY THAN ANTICIPATED, AND SO I INITIATED A VERY QUICK DSCNT BY LOWERING THE COLLECTIVE FULL DOWN. THIS PRODUCED A HIGH RATE OF DSCNT (NOTE THAT THERE IS NO VSI IN THE HELI TO DETERMINE THE RATE OF DSCNT). APPROX 50' FROM THE RWY I INITIATED A DECELERATION MANEUVER WHILE I WAS INCREASING THE PWR AND ROTOR PITCH BY PULLING UP ON THE COLLECTIVE. A DECELERATION MANEUVER WAS REQUIRED BY MY HIGH RATE OF DSCNT. THE ACFT STABILIZED APPROX 15' ABOVE THE RWY AND FROM THIS POINT A VERY SLOW, PRECISE LNDG WAS MADE. AFTER LNDG ONRWY 27 I HAD SPOKEN A COUPLE OF SENTENCES TO MY OBSERVER AND WAS INCREASING THE PWR BY RAISING THE COLLECTIVE WHEN BOTH MY OBSERVER AND I HEARD THE SOUND OF AN ACFT ENG. WE BOTH LOOKED TOWARD THE SOUND WHICH WAS TO OUR LEFT AND OBSERVED A FIXED WING ACFT, SMA Y, APPROX 60' LAT FROM OUR POS AND 20' ABOVE THE RWY. THE SMA Y WAS IN A 30 DEG LEFT BANK AND EXECUTING A GAR. THEREAFTER, WHILE STILL AT VERY LOW ALT, THE SMA Y QUICKLY ENTERED A 30 DEG RIGHT BANK, CROSSED THE CENTERLINE OF RWY 27 AND CONTINUED CLBING TO THE NW. WE LOST SIGHT OF THE ACFT. WE DEPARTED RWY 27 AND CONTINUED LOOKING FOR THE FIXED WING ACFT. ON XWIND WE STILL HAD NOT MADE VIS CONTACT WITH THE ACFT. JUST AFTER TURNING FROM XWIND TO DOWNWIND WE MADE VIS CONTACT WITH THE ACFT. THE ACFT WAS AT OUR 7 O'CLOCK POS COMING TOWARDS US AT A HIGH RATE OF SPD. THEREAFTER, WE LOST SIGHT OF THE ACFT AS IT ENTERED OUR 6 O'CLOCK POS AND REAPPEARED AT OUR 4-5 O'CLOCK POS, APPROX 1/2 MI BEHIND THE ACFT. THE SMA Y CONTINUED TO ACCELERATE AND POSITIONED HIS ACFT AT OUR 3 O'CLOCK POS APPROX 50-60' LAT. THE SMA Y CONTINUED TO FLY AT OUR 3 O'CLOCK POS FOR APPROX 30-60 SECS. HE THEN ACCELERATED TO OUR 1-2 O'CLOCK POS APPROX 2000' IN FRONT OF OUR ACFT. HE THEN MADE A 90 DEG LEFT TURN WHICH PASSED DIRECTLY IN FRONT OF OUR ACFT AND CROSSED PERPENDICULAR TO OUR DOWNWIND FLT PATH APPROX 2000' IN FRONT OF OUR ACFT. THE SMA Y THEN DSNDED TO APPROX 600' MSL ON XWIND, AND FLEW AT THAT ALT DOWN RWY 27. THEN THE ACFT TURNED XWIND, DOWNWIND AND BASE AT THE SAME ALT AND FINALLY LANDED ON RWY 27. THEREAFTER, THE ACFT TAXIED OVER TO ONE OF THE HANGARS AND PARKED. THIS INCIDENT AROSE BECAUSE OF 2 PRIMARY FACTORS. THE FIRST FACTOR IS THAT THE MIL EQUIPS MANY OF THEIR ACFT WITH ONLY UHF RADIOS. THESE ACFT ARE OPERATED IN THE CIVILIAN ATC SYS WHERE THE PRIMARY RADIO IS VHF. AT UNCONTROLLED ARPTS THIS PREVENTS THE MIL ACFT FROM RECEIVING POS ANNOUNCEMENT FROM CIVILIAN ACFT OVER THE UNICOM OR CTAF. THE SECOND FACTOR IN THIS MATTER IS THAT A FIXED WING ACFT TOOK ADVANTAGE OF A LNDG ACFT AND MISJUDGED DISTANCES BTWN THE 2 ACFT IN VIOLATION OF THE FARS.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.