Originally Posted by
PEI_3721
JT, zzuf, Clan, et al, interesting views.
zzuf, 'Limit is shown by …'; actually its demonstrated for certification (playing with words - the manufacturer shows that the requirement is met).
However, the lowly flight-crew have no indication, no show and tell, no instrument or tech description; thus take it easy as JT #29.
zzuf, Back to #20, or without load indication, not knowing doesn't matter because you can't get there #30 ?
Clandestino, we are facing the same direction.
However, is your application the 0.666 factor to the AFM 'normal g' limit a precaution because the pilot has no indication (good practical advice), or a real limit to be respected ?
Three Wire, re A4; as I recall a high 'g' pull up with asymmetric slats (one hangs up - not enough grease) resulted in significant rolling 'g'. There was a video of a TA4J shedding a large drop tank.
If you wish to become pedantic about compliance with certification standards, perhaps this will help:
25.1 Applicability.
(a) This part prescribes airworthiness standards for the issue of type certificates, and changes to those certificates, for transport category airplanes.
(b) Each person who applies under Part 21 for such a certificate or change must show compliance with the applicable requirements in this part.
There are plenty of times where "acceptable means of compliance" can mean other than demonstration.
Your comment on "not knowing because you can't get there" was done to death before any certification authority accepted the manoeuvre limiting features of most FBW aircraft. I suggest some research into the development of the current FBW standards.
Your suggestion that 2/3 factor could even be considered to be due to what instrumentation is fitted does not stand much scrutiny for what is a structural design standard.
Strictly speaking, there is no limit in the AFM this is a structural design standard for which compliance has been SHOWN during certifcation. There are plenty of structural design standards not mentioned in the AFM.
The suggestion that transport aircraft should be fitted with accelerometers has been discussed many times as are "alpha" indicators. Demonstrably, the certification authorities have not been convinced.