Page:Report of the Board of Inquiry into the Helderberg air disaster.djvu/47

Rh

The 800 Hz test tone is introduced on all four CVR channels. After about 6 seconds rapid changes in amplitude (warbling) commence. After another 5 seconds the signal ends. As noted above (in paragraph 1.1 p ), these concluding sounds indicate that the audio input and test signal wiring were being affected by the fire.

The tape ran for exactly 29 minutes and 52 seconds. It was noted that neither the last HF communication with MRU at 23:14:00 nor the first VHF communication with MRU approach control at 23:48:51 was recorded on the CVR.