Regarding the horizontal tailplane on 707 aircraft, PanAmerican lost a freighter approaching Lusaka many years ago...upon selecting flaps 50 for landing one of the horizontal stabs detatched (due to severe corrosion to the attach fittings), and the airplane impacted vertically.
An Airworthiness Directive was issued in short order, to inspect these tailplanes, and many were found with corrosion and attach fittings fractures.
So, if an engine cowl detatched, struck the horizontal stab, which had not been inspected properly...well, this would clearly not be good.
Just a thought.
Horizontal tailplanes, and their operation (especially jammed stabs...had one of those personally) on 707 aircraft...many problems over the years, without a doubt.
With a jammed stab, Boeing provided a superb alternate method of pitch control...split spoilers....known technically as, spoiler bypass.
L1011...same/same.