Rivet,. .. .The mod was actualy the addition of the air ground interlock, the airspeed switch has always been there.. .. .The mod was embodied many years ago when Boeing had several RATs deploy because of jet blast while queueing for T/O. (ground idle is borderline for the 47% N2 signal). .. .B Shoe, I owe you an apology, I thought the breakers had been pulled during maintenance T/S I did not imagine anyone would be daft enough to start pulling cb's in flight (outside of those specified in the QRH).. .. .Cheers.