B737-800 First Officers reported this particular 737 has yaw control problems. One pilot reported uncommanded rolls and the other pilot reported receiving information from other pilots and their own experience of perpetual problems. Both FOs refused to fly the aircraft.
Synopsis
B737-800 First Officers reported this particular 737 has yaw control problems. One pilot reported uncommanded rolls and the other pilot reported receiving information from other pilots and their own experience of perpetual problems. Both FOs refused to fly the aircraft.
Narrative
This 737 has a history of a yaw damper malfunction. This issue has been written up; and signed off; multiple times. The MEL states that flying into known moderate or above turbulence is prohibited; and if encountered; the crew must exit the condition. Flaps 40 landings are also prohibited. On two instances of flying this aircraft; the crew unknowingly flew into moderate + turbulence. In both instances; the autopilot was engaged at the time the aircraft was inadvertently flown into said turbulence. In both instances; the crew encountered violent and abrupt yaw and rolling motions; and the autopilot disengaged after failing to maintain directional control of the aircraft. During both flights; the aircraft went into an abrupt un-commanded roll after the autopilot was disengaged; and the crew received a bank angle warning. I was scheduled to fly this aircraft; and noticed that not only was the yaw damper still MEL'd; but both flight directors were MEL'd. Upon speaking to other crew who have flown this aircraft; it was noted that the aircraft was having Mode Control Panel (MCP) issues; also inducing rolling motions and flight director failures. A write up by the Captain (CA) of another crew stated that the aircraft was unsafe to fly at night. Due to all MEL issues; and based on previous flights with the potential for turbulence in the vicinity of ZZZ1 (Cumulonimbus clouds at 2200 ft. were being reported) I made a call to the VP of safety voicing my concerns. I then spoke with the 737 program manager; as well as the Chief Pilot; and told the Captain my reasoning for refusing the aircraft. I was pulled off the flight; put on reserve; and the plane departed for ZZZ1 around XA00Z. Avoiding turbulence is an instance in which pilots are relying on PIREPs to avoid it. Another determining factor would be weather at the departure and arrival airports. One could infer that there would likely be turbulence in the presence of cumulonimbus cloud formations. In these two instances; the moderate turbulence was unreported and a surprise to the crew. On both flights; the crew reacted accordingly to regain aircraft control; and exited the turbulent condition as soon as possible. In any instance where the aircraft had the MEL signed off; a new write up was entered into the logbook. The narrative by the CA who wrote that the aircraft was unsafe for flight at night should have been taken seriously. If a Captain has been signed off and passed check rides; and been made PIC of an aircraft; Maintenance should take what he or she says into serious consideration when determining if an aircraft is safe to fly; or if issues need to be resolved before the aircraft is flown again. Multiple crews have not only written up the same issues with the aircraft; but have informed maintenance that they have persisted. My encounter with the aircraft rolling un-commanded into a severe bank when the autopilot could not maintain directional control is not unique; nor are the Multi-function Flight Displays (MFD's) flickering on and off or navigational issues with regard to the aircraft. I would suggest that; in the future; any aircraft that has months of the same write up; be pulled off the line and grounded until a fix can be put into place. Not only does this ensure that safety is a priority; but that pilot concerns are taken seriously.
Second reporter narrative
I was scheduled to fly this 737 from ZZZ to ZZZ1 and back. My report time was XC20L. I had cited safety concerns with this aircraft; and had already notified operations earlier that afternoon (around XB00L) I would not be accepting the aircraft upon arriving due to the issues plaguing the aircraft; reports from other pilots; and my own personal experiences. I was informed that there would either be a tail swap or the flight would be canceled by the Chief Pilot. I arrived early; and when I noticed there had not been a tail swap or a cancellation; I called Dispatch. They informed me they had not been told about a cancellation or tail swap. While at the airport; I waited to see what would transpire. Shortly thereafter; crew resources called me and told me I was free to go home; after I had shown up for duty. However; they illegally assigned me to a reserve period beginning at XA00L that morning; ending at XC00L that evening. This should have started at my original report time; and followed 8 hours after that. They illegally assigned me a reserve that ended before my report time. Crew scheduling assigned an illegal assignment after pulling me off a flight after citing safety concerns. The Reserve period should have started at XC20L; and going until the following morning. I informed the company of the safety concern early enough to where I could have been taken off the flight before my report time.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.