Narrative:

Aircraft X was cleared for takeoff by the tower. Following rotation and initial indication of a 'positive rate' the PIC requested from the safety pilot gear retraction. At approximately 30' AGL the aircraft presented unusual flight control forces. The aerodynamic forces on the tail caused the nose of the aircraft to favor a 'nose low' attitude. The PIC counteracted the downward force on the tail through a necessary application of extreme backward force. The trim system was utilized; as per type design to relieve this pressure in the hope to gain a positive pitch attitude. The PIC was forced to again increase the back pressure on the yoke to prevent the aircraft from sinking back into the runway. As the airspeed was increasing; the control forces required to counteract the downward force on the aircraft was approaching max deflection of the elevator. The power was reduced to prevent the aircraft from accelerating; which was determined as having a potential to exceed the flight controls capabilities. The aircraft was not climbing as it was approaching the end of the runway; with obstacles in front of the aircraft being in the flight path of the aircraft. Landing was not an option as the airspeed; configuration; and altitude; with respect to the runway remaining (approximately 1;500 feet) were out of allowable limits. The safety pilot called 'use the trim!'. The PIC stated 'I have no more elevator; the trim isn't working'. The PIC looked at the back of the aircraft as he deduced that the elevator had disconnected and the aircraft had no vertical axis flight control. The end of the runway was nearly under the nose of the aircraft as the PIC ran the trim system in another burst through the yoke electric switch. The pressure increased. The manual trim wheel was run in the 'nose up' direction with the same result. At this point the PIC elected to run the trim wheel in the 'nose down' direction. The nose down pressure relieved slightly. The PIC immediately added more opposite direction trim. The aircraft flight path stabilized and the aircraft began a positive rate of climb. Once the aircraft flight path provided obstacle clearance and ensured the aircraft was no longer out of control; the trim system was stopped. The PIC requested the safety pilot to contact tower and request and immediate return to the departure runway. The maximum altitude achieved during the flight was 600 feet in the pattern as the PIC was hesitant to change flight control position; airspeed; and configuration change until it was determined the aircraft was in a position to land without application of excessive flight control movements. The PIC knew the aircraft trim system was installed incorrectly (backwards); but was unsure as to the usability and reliability of the elevator. The aircraft was landed on runway without incident; no emergency declaration was exercised (there was not enough time to mobilize the equipment; and priority handling would have not accelerated the position to land). The aircraft was turned over to maintenance with the report 'the trim system was installed backwards'.

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Original NASA ASRS Text

Title: A C-414 air crew shortly after takeoff experienced aerodynamic forces on the tail of the aircraft favoring a nose low attitude. Electric and manual trim exacerbated the condition. The pilot then ran the trim in the direction of nose down resulting in a positive rate of climb. 'The trim System was installed backwards'.

Narrative: Aircraft X was cleared for takeoff by the tower. Following rotation and initial indication of a 'positive rate' the PIC requested from the safety pilot gear retraction. At approximately 30' AGL the aircraft presented unusual flight control forces. The aerodynamic forces on the tail caused the nose of the aircraft to favor a 'nose low' attitude. The PIC counteracted the downward force on the tail through a necessary application of extreme backward force. The trim system was utilized; as per type design to relieve this pressure in the hope to gain a positive pitch attitude. The PIC was forced to again increase the back pressure on the yoke to prevent the aircraft from sinking back into the runway. As the airspeed was increasing; the control forces required to counteract the downward force on the aircraft was approaching max deflection of the elevator. The power was reduced to prevent the aircraft from accelerating; which was determined as having a potential to exceed the flight controls capabilities. The aircraft was not climbing as it was approaching the end of the runway; with obstacles in front of the aircraft being in the flight path of the aircraft. Landing was not an option as the airspeed; configuration; and altitude; with respect to the runway remaining (approximately 1;500 feet) were out of allowable limits. The safety pilot called 'Use the Trim!'. The PIC stated 'I have no more elevator; the trim isn't working'. The PIC looked at the back of the aircraft as he deduced that the elevator had disconnected and the aircraft had no vertical axis flight control. The end of the runway was nearly under the nose of the aircraft as the PIC ran the Trim system in another burst through the yoke electric switch. The pressure increased. The manual trim wheel was run in the 'Nose Up' direction with the same result. At this point the PIC elected to run the trim wheel in the 'Nose Down' direction. The nose down pressure relieved slightly. The PIC immediately added more opposite direction trim. The aircraft flight path stabilized and the aircraft began a positive rate of climb. Once the aircraft flight path provided obstacle clearance and ensured the aircraft was no longer out of control; the trim system was stopped. The PIC requested the safety pilot to contact tower and request and immediate return to the departure Runway. The maximum altitude achieved during the flight was 600 feet in the pattern as the PIC was hesitant to change flight control position; airspeed; and configuration change until it was determined the aircraft was in a position to land without application of excessive flight control movements. The PIC knew the aircraft trim system was installed incorrectly (backwards); but was unsure as to the usability and reliability of the elevator. The aircraft was landed on Runway without incident; no emergency declaration was exercised (there was not enough time to mobilize the equipment; and priority handling would have not accelerated the position to land). The aircraft was turned over to maintenance with the report 'The trim System was installed backwards'.

Data retrieved from NASA's ASRS site 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.