Hello Meikleour,
Surprised and impressed you did a 2-engine G/A on the a/c. I guess it was part of the P1 sylabus, whereas mine was P2.
The situation faced by the RAAF crew at East Sale as Old Fella explains it (failure to reinstate rudder boost before demonstration of two engines at idle on one side) was not, of course, in any SOP. But by discussing the implications of loss of rudder boost in the 3-engine case, and the seriousness of the case of 2-engines out on the same side even with rudder boost available, we may have given some idea of the catastrophic nature of the problem.
Furthermore, this quote from earlier in the thread by IGh suggests the problem of recovering control in the event of simulated failures may be more complex than one might think, although it seems not to have applied in the RAAF case:
"Rudder control system characteristic: in event of shutdown/failure of Auxiliary System pumps rudder system will NOT automatically revert from Powered mode to Manual mode. If rudder boost is lost the Rudder will suddenly center (since tab is Anti-servo); to regain use of rudder pilot must first center the pedals (bring tab into servo range). If unable to achieve Manual Reversion, LoC could result even with speed faster than Vmca. [AIAA Paper #71-793, TGF&HFM, pg 15-6."
Yes, thanks for reminding me that "... if the rudder boost failed and then an engine was lost then the s.o.p. was to fly the approach as a 2-eng SYMMETRICAL approach ..." A visit to my shed reveals a photocopy of the Emergency Check List, which confirms that, and the 3-eng Vmca of 180 kt. Elsewhere, it confirms the 2-eng (asymmetric) Vmca of 147 kt (with rudder boost). It also states that it may not be possible to go-around with #2 and #3 shutdown, due to slow flap retraction and gear-retraction complications.
What a beast! My problem getting it into perspective now, however, is that I never flew the B747 or any other 4-engined jet with widely-spaced engines. I imagine the Galaxy and the early Classics may have shared the 707's lacklustre performance, but at least they would have had some redundancy in their rudder systems.
Last edited by Chris Scott; 7th Oct 2015 at 16:25.
Reason: Correction in para #2, sentence #1. Correction in para #3, sentence #1.