CHIEF WARRANT OFFICER 4 DAN KIRBY
As aviation professionals, we all try our very best to accomplish the mission. Sometimes, this desire to produce the best results in the minimal amount of time works against us. This article highlights an instance where my desire to get the job done in the least amount of time turned into a Class C accident.
I was assigned to the 1-159th Aviation Regiment as a Black Hawk maintenance test pilot. We were about three months into a nine-month Bosnia rotation, flying a pretty heavy schedule supporting the peace-keeping efforts. Having flyable aircraft was a priority, so anytime a helicopter was in maintenance it detracted from my unit’s ability to complete the mission. On this particular day, I was performing a track and balance. This procedure involved flying the aircraft with a piece of test equipment called a RADS (Rotor Analysis and Diagnostic System) attached to it.
When performing a track and balance, the pilot flies the aircraft at different airspeeds while the RADS measures vibrations and relative blade height. At the end of the flight, the RADS provides an adjustment solution that requires adjusting weights and control rods to bring the aircraft into an acceptable vibration limit. After the adjustments, the pilot flies the aircraft again to verify the amount of vibrations. If the vibrations are not within limits, the RADS will give another solution and the process is repeated. Once the aircraft is within limits, the pilot takes it out for one more flight to check the autorotational capabilities, which could have been affected during the adjustment of the control rods.
We were having problems getting the vibrations within limits and had already flown the aircraft and made adjustments five times. I really wanted to get the aircraft to a fully mission capable status so it could fly a mission later that afternoon. On the sixth flight, I started the helicopter and began to turn on the avionics. I inadvertently placed the transponder control in a position that caused the Mode 4 code to be dumped. This one act was the first mistake in a chain that resulted in the accident.
At that time, all aircraft in Bosnia were required to transmit a Mode 4 code while in flight. To reload the Mode 4 code, the nose door of the aircraft had to be opened. I asked the crew chief to get out of the aircraft and reload the Mode 4 for me rather than doing it myself, which would have involved me shutting down the aircraft, taking off my safety harness and getting out of the helicopter. If I did it myself, it would have taken about an additional 15 minutes. I saw this as an effective measure to reduce the amount of time required to correct this problem.
The crew chief exited the aircraft, opened the nose door, loaded the Mode 4 and closed the nose door. When he was finished, he gave me the thumbs up and got back into the helicopter. I immediately called for clearance to take off and began the procedure to get the RADS readings. The flight was going well and all the readings were within limits. The final reading was taken at 145 knots and it was good.
I was happy that the track and balance was finished and wanted to go right into the autorotational check without landing the aircraft and removing the RADS. I asked the crew if anyone objected. The co-pilot and the crew chief had no objections and were as glad as I was to get the job done as quickly as possible. So, I gave a safety brief to the crew and proceeded to an area that would be safe to perform the check.
An autorotation check involves bringing both engines to idle and allowing the aircraft to descend without engine power. This is done to ensure the rotor system will slow the decent of the aircraft and allow it to land safely if the engines fail in flight. When I was established in the autorotational area, I began the autorotational check by lowering the collective and bringing the engine power control levers to idle. The aircraft began to descend at about 2,000 feet per minute. This changed the flow of air over the nose door from downward, which acted to keep it closed, to upward, which asserted pressure upward.
None of us realized the nose door of the aircraft had not been latched closed. It is usually held shut by two latches and a lock assembly. The lock assembly is there primarily to secure the avionics equipment located in the nose of the aircraft. It is not designed to keep the door closed while the aircraft is in flight. When the crew chief closed the nose door after loading the Mode 4, he locked it with the key but did not secure the two latches. After just a few seconds of establishing a descent, the nose door flew open, sending the RADS camera, which was mounted on the nose door, through the center windshield. This caused the nose door to jam fully open, completely blocking my forward field of view.
I recovered from the autorotation by bringing the power control levers back to the normal fly position and arresting the descent. I had to fly the aircraft back to the airfield by looking out the side door windows because the nose door remained jammed open. Luckily, the nose door did not become detached from the aircraft or it could have possibly been sent through the main rotor and further complicated matters.
After landing, we got out to assess the damage. The fiberglass nose door was cracked and punctured, the RADS camera was broken and the prop rod used to hold the door open during maintenance broke off at one end and was driven into the ADF receiver as the nose door slammed shut on landing. As we already knew, the center windshield was broken. A technical inspection/report of survey revealed more than $12,000 in damage. Luckily, none of us were injured, but it could have easily gone the other way.
So, who was at fault for this accident? Ultimately, I was because I was the pilot in command. Does it really matter? Not really. The whole crew was put into a position of danger because of the mistakes that were made. How could this have been avoided? We could have slowed our pace and double-checked instead of taking every opportunity to save a few more seconds. Like the old saying goes: Haste makes waste.