PPRuNe Forums - View Single Post - 737-500 missing in Indonesia
View Single Post
Old 9th Feb 2021, 08:48
  #491 (permalink)  
fdr
 
Join Date: Jun 2001
Location: 3rd Rock, #29B
Posts: 2,956
Received 861 Likes on 257 Posts
Flaps,

There is almost no chance this aircraft spun. I didn't say it did, I was referring to another post that had suggested the term, and I was indicating that it was unlikely. Go back, and read what was written. On wind shear, I did not say the sim got 180/s, it did not, it did go nose flat 2 times in a row while whizzin' about. Got to thank the guys for repeatability.

The DFDR will tell the story, the guys will already know in this case what happened, they may not know why. It seems to still fit around a clutch pack issue that left a thrust lever at a climb thurst level and brought only one back to maintain speed, which then went pear-shaped. The weather adds distractions and complicates both the detection and the recovery. In this sort of bingle, it's going to be a spiral dive, not a spin, at least to start with. Without being stalled, KCAS is going to wind up quickly, making a stall less likely along with recovery.




As you are from south of the border, it's probable that the sim you refer to is one of the two that I evaluated at the end of 1994 for fidelity in respect to control loss. Hope they were improved in between. using the available data at that time, neither the 300 nor the 400 sim did a great job of the control authority that existsed, and they didn't match the rates that were achieved in 427. Also did run-throughs of the 585 event and it was also not very close to the event data which was pretty sketchy anyway. The classic was different to the 200 but not that much. The 585 event I had queries about that being an off-axis gust front vortex and the maths had suggested that the roll, pitch and yaw needed to plonk in 9.x seconds (its a while ago...) were achievable from the vortex alone. There were contemporaneous reports of severe gust activity across the area of the flight path, The CVR was harrowing. Yes, the 427 rudder was consistent with a rudder reversal and got to take my hat off to George S for holding out for the tests to be done until failure was finally detected by P-H. the SE event, also consistent with the rudder. 585 didn't need the rudder reversal, and it also did not match the flight conditions that were needed to trigger the problem with the single spool double acting servo. 585, like CAL006 didn't stall, nor has the SJ182 likely to have stalled.

Last edited by fdr; 9th Feb 2021 at 10:50.
fdr is offline