S76 Handbook CAT A V-Speed Considerations You should already be familiar with this calculation from studying the course notes, so like all RQG's this is simply extra revision Answering these Category A MTOW V1/V2 questions requires use of the graphs on Page 28 and Page 29 of the S76 Handbook. As with most graphs in the handbook there are distortions and fading so there is always an inherent accuracy problem This RQG is a little different to all other RQG's because it only has ten basic data sets with small variations within each set of configuration. You can do each set starting with either Page 28 or Page 29 by ticking the box at login. Sets nine and ten are the most challenging/frustrating I'm just an oldschool pilot and script coding accurately graph data with five variables is beyond my ability, but you don't need many examples to be able to understand how these questions need to be done When answering these questions an accuracy of plus/minus 1 knot for V Speeds is acceptable, so don't stress if you don't get the exact answer we give but are always within 1 knot each time. MTOW within plus/minus 50 lb is good and within 80 lb is the comfortable limit NOTE - If your V1/V2 is a knot different to the pair shown in the solution your final MTOW might be around 100 lb different to that shown. The 50 lb to 80 lb tolerance is applied only to the same V1/V2 shown in the solution, but on exam day CASA would allow for a one knot difference in the V speeds You can use the data sets for three different calculations with the starting point being the usual PA/OAT/HWC and RTOD/CTOD or you can tick the box and start with a given PA/OAT/HWC and required MTOW and backtrack to find RTOD/CTOD. A final twist is to tick the box and practice back tracking the graph to find the limiting OAT for a given set of conditions When you are asked to calculate the Cat A MTOW and you are given data for both RTOD and CTOD, then you follow the process in this RQG to determine if the V1 or V2 is the most limiting speed for the takeoff from Page 28 and then the MTOW from Page 29. As a general rule you need more CTOD than RTOD for a takeoff, however because RTOD is basically the physical length of the runway available it usually becomes the main issue, as finding clearway to increase the CTOD available is common in real life. Remember V1 and V2 are a matching pair of V speeds which are always 10 knots apart, so you are really searching for the more limiting (lowest) pair of speeds to be then used over on Page 29 to get the actual MTOW Also remember that a Balanced Field happens when the RTOD required is the same as the CTOD required. For the S76 in this exam that is rare but can happen, however the RTOD available may be given as the same as the CTOD available and while that situation is not a Balanced Field, it may also occur in some questions. When it does occur the V2 speed will most likely be the limiting part of the Vspeed pair Be careful on Page 29 when plotting Pressure Height/OAT combinations that reach the top block of dotted lines representing Torque Limits. You can see where the 10 degree, 0 degree and -10 degree lines change from solid to dotted and follow paths slightly under the top edge of the graph. When you are asked to calculate the RTOD/CTOD and you are given data for the required MTOW then you follow the process in this RQG to determine the required V1 or V2 from Page 29 and then backtrack to determine the required RTOD/CTOD on Page 28 Finally as mentioned earlier, you can also use this RQG to do reverse engineered calculations of the limiting (maximum permitted) OAT for given takeoff conditions and requirements. The same basic process can be used to find any limiting condition on any graph (eg.. limiting HWC or PA) when you are given all of the other data. Basically you start drawing all the lines you can with the information you have and eventually they will intersect at the missing variable or limitation This RQG is a brand new concept using new technology, so if you find something clearly wrong please let me know. Wazza Please Click Here to return to the login page.