Skylane 182/RG Turbo Skylane/RG
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Flight Crew Last 90 Days 40; Flight Crew Total 360; Flight Crew Type 50
Situational Awareness; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft; Human Factors; Procedure
After departing on a test flight to return the aircraft to service after maintenance; at 1;100 feet MSL (in the midst of our x-wind turn); the aircraft began to pitch steeply toward the ground which was un-commanded by both me; pilot flying (PF) and the pilot not flying (PNF). My initial thought was that the auto pilot had engaged; and was starting a descent; but after verifying that it had not; and holding the nose level using much strength; and both hands on the yoke; I called for my other crew member; the PNF to apply back pressure on the yoke with me. After the PNF asked me if we should declare an emergency; I directed him to do so (saying that the nature of the emergency was a loss of elevator effectiveness) on the tower frequency; which he did; and our final RWY that we requested was the longest; widest RWY at the airport. I also asked him to tell the tower to 'roll the trucks' (fire trucks) in anticipation of a hard or crash landing due to the diminished effectiveness of our elevator at that point. We were cleared to land; and assured that the fire dept. had been called. On the downwind leg of the pattern; we were both using much of our strength and attention just to hold the nose level; and throughout the incident; I had been incrementally adding nose-up elevator trim in an effort to relieve the pressure (strong nose down tendency) that the aircraft was exerting against our efforts to bring the nose up. We turned base still unable to relieve the extremely strong nose down tendency; and we both had serious doubts about our ability to flare the airplane and make a safe; normal landing. He searched for the electric trim circuit breaker thinking that it may have been an extreme runaway trim situation; while I devoted my attention to keeping the nose level. The majority of the time; he stayed on the controls with me; aiding in the extreme back pressure required to keep the airplane from nosing into the ground. He was unable to locate a specific 'electric trim CB'. It occurred to me at that point on base; that because work had been done to the trim system (this the mechanic had told me prior to the flight); there may be a reversal of sorts with something in the elevator trim system. I proceeded to carefully; and counter intuitively apply nose down elevator trim; and after several seconds; was able to relieve the extreme nose down tendency of the aircraft. Immediately I knew that something had been reversed after the aircraft reacted that way. We proceeded to make a normal approach and landing; with no damage done to the aircraft or any other property. The fire trucks then followed us back to the ramp; and the fire fighters took down my information as pilot flying; as well as a brief synopsis of the issue we had been dealing with that caused us to declare the emergency. I believed that the elevator trim actuator had been installed 'backwards'; however found out later that the chains had been crossed leading back to the actuator. A larger inspection panel on that part of the airplane would allow the mechanics to better see the condition of the chains and cables; as well as allow them to verify that they are attached properly. The current manufacturers panel/opening requires that they use a mirror and flashlight to verify that important control mechanisms are properly aligned and connected. Having another crew member on board in this situation helped to allow me to focus on keeping the plane from nosing into the ground; while he talked on the radio; did some troubleshooting; and helped relieve the back pressure that I had to apply to keep the aircraft from nosing down. Without him; I doubt the outcome would've been nearly as successful; without damage or loss of life. Having a PNF on board allowed me to use my strength to fly the aircraft; and not worry about removing my hand from the yoke in a situation like this to do things such as change the configuration of the aircraft for landing (which he did).
The landing was uneventful and we were met by ground personnel to discuss what had happened. We later talked to the mechanic and saw that the elevator trim was installed backwards which confirmed our beliefs about the problem. The PIC had done a thorough preflight inspection and we ran all checklists necessary for the flight and the problem was not discovered. During the event we communicated well which I believe had a positive affect on the outcome of the flight. ATC was informed and also very helpful with regard to their role.
Two pilots testing a C182 after maintenance had been performed discovered a strong nose down pitch tendency that could not be trimmed out and required the strength of both pilots to maintain level flight. Remembering that maintenance had been done on the elevator trim system; the flying pilot attempts nose down trim and finds the pressure reduced. More nose down trim is applied until the aircraft is in trim and flying normally. A normal landing ensues.