The Roller Coaster technique in Boeing 737's
Looking at my February 1, 1982 737-200 Pilot Training Manual, page 04.80.31 under the heading Recovery from Severe Out-of-Trim. It discusses a runaway and manual stabilizer operation.
Quote: In an extreme nose-up out-of-trim condition requiring almost full forward control column, decelerate, extend the flaps and/or reduce thrust to a minimum practical setting consistent with flight conditions until elevator control is established. Do not decrease airspeed below the minimum maneuvering speed for the flap configuration. A bank of 30 degrees or more will relieve some force on the control column. This, combined with flap extension and reduced speed, should permit manual trimming.
If other methods fail to relieve the elevator load and control column force, use the "roller coaster" technique. If nose-up trim is required, raise the nose well above the horizon with elevator control. ( my note: This may require both pilots to use their combined strength.) Then slowly relax the control column pressure and manually trim up. Allow the nose to drop while trimming. Repeat this sequence until the airplane is in trim.
If nose-down trim is required, slowing down and extending the flaps will account for a large degree of nose-up pitch. If this does not allow manual trimming then the reverse "roller coaster" can be performed to permit manual trimming.
In subsequent issues of the Boeing 737 FCTM these vital paragraphs were omitted. Consequently, we were never shown the "roller-coaster" technique in the simulator or even discussed at briefing. The result being a significant number of Boeing 737 flight crew nowadays are unaware of the roller-coaster method of relieving elevator forces in event of a runaway stabilizer trim. Nor were the pilots of the two 737 Max aircraft that crashed