This in response to Outside Loop:
The Robinson helicopters do have a design defect and this makes them unsafe to fly. It is the restrictions placed on them by the FAA directive that in fact makes them safe to fly "now" as long as the aircraft is operated within those restrictions. I will concede that Bell rotor systems are subject to loss of control in a low G situation. in addressing the recovery from a loss of control in low G on a Robinson if the pilot follows the POH instructions the design defect in the rotor head can result in loss of the aircraft. Reading several postings above another writer stated that the Robinson test pilot explained to him that when you pull aft cyclic to correct for loss of control you add in a “Tad” of left cyclic. It appears to me that he is aware of the design defect, and by pulling a tad of left cyclic, he is compensating for the design defect. I ask again, if he is aware of the problem then why isn’t the instruction to use a “Tad” of left cyclic in the emergency operating procedures?
Regarding Frank and his lawyers, I had previously mentioned that I have a lawyer friend in California that tried three cases against Robinson and he was awarded millions of dollars for his clients, but was unable to collect a cent. Because, Frank Robinson keeps his money in offshore accounts and he leases everything in his plant including the building. On paper, Frank Robinson appears to be as poor as a church mouse.
Regarding the crashes in Australia this is all I have.
1) Julia Creek, Australia Ferry flight VH-HBK Mast Separation 06-15-92
2) Brighton Downs Station, Australia Business Flight Tail boom and cockpit strike 07-17-95
The FAA advisory was added to the POH on or about 13-January-1995.
The loss of the rotor blade you mentioned was not in the NTSB report.
This is for 212 Man:
The reason that sideslip and out of trim flight are restricted on the Robinson Helicopters is because of the rotorhead problem. If you perform those elements of the restricted flight envelope the flapping loads will be so sever that it could cause rotor failure or, mast separation. The questions in my report that were addressed to the FAA and Robinson were couched in such a way that they would have to give a full explanation of how the helicopters were certified and what tests were run to verify that the helicopter was in fact certifiable. It is my contention that Frank Robinson as the DER for the FAA signed off on the testing knowing that the rotor system was in fact defective by FAA definition. Also I asked questions of the FAA and Robinson relative to the rigging procedure to find out how the FAA approved the design of the flight control system when it was in violation of FAA design guide lines.
At my last count (as of 1976) there were over fifty Bell Helicopters that lost their rotor due to Low G flight and subsequent mast bumping.
Regarding the flapping capability of the 214 ST rotor head that is not true. The 214 ST has the same type of rotor head used on the 214 and similar to that used on AH1-J. The 412 uses similar technology but it has four blades. The rotor has the capability to flex due to coning action and in response to flight loads but the blades do not flap as they do on the Robinson rotor system.
Getting back to your first statement about having limits on sideward flight. The certification requirements require the demonstration of sideward flight but they do not specify an upper limit. The demonstration is in fact a means of determining and specifying the limiting speeds of sideward flight. The same is true for rearward flight. These limits are then published in the POH for each helicopter. The Robinson is restricted from sideward flight and out of trim flight yet the FAA design regs stipulate that both flight parameters be demonstrated in order to gain certification. If the Robinson can’t do it now, how did they demonstrate this capability during certification?
------------------
The Cat