PPRuNe Forums - View Single Post - MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
Old 25th Aug 2019, 02:25
  #2021 (permalink)  
CurtainTwitcher
 
Join Date: Jul 2014
Location: Harbour Master Place
Posts: 624
Originally Posted by Notanatp View Post
The climb was arrested when flaps retracted. The climb was shallow to begin with. Look at the Reuters graphics comparing the ET302 accident flight climb profile with other flights leaving Addis Ababa and with the Lion Air 610. (Google "graphics reuters Ethiopia-airplane") The graphic shows that one other flight out of Addis Ababa had a similarly shallow departure climb and had to go around the east side of the mountain to the southeast.

Also, it looks to me like they pitched up was pretty high immediately after wheels off and then the PF forced the nose down with forward control column pressure.

As I have commented previously, I believe ET302 was over Regulated Take Off Weight. The Preliminary Report says they were below RTOW, but if you look at the weight and balance information, they assumed around 167 lbs./pax, INCLUDING carry-on bags. If you use 190 lbs./pax, they were over by around 2,000 lbs. And if that's correct, then the reason appears to be that they were ferrying fuel (to save money by not paying for it in Nairobi?). Perhaps this was standard EA practice and explains the shallow climb of one of the other flights shown in the Reuters graphic.

If they were overweight, and it affected take-off and initial climb performance, then that might explain why the crew failed to retard the throttles, even after the overspeed clackers started going off at 05:41:20 and 05:41:32.

In any event, the time required to respond to activation of MCAS, or recognition of any stab trim abnormality, appears to be irrelevant to both JT610 and ET302. Both crews may have been startled initially, but both crews maintained control of their aircraft for minutes, not seconds, and any initial delay in recognizing that there was a stab trim problem wasn't what caused the loss of the airplanes.
Is 2000 lbs / 900kg over RTOW on two engines going to have a dramatic impact on the climb performance to the extent it is discernible in a newspaper graphic (Reuters link to graphics), especially given the scale? Single engine, yes, but that wasn't the scenario.
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