Very interesting footage and an eye-opener in regards to what could be found and what the possible remains of an aircraft may look like.
The application of Side-Scan Sonar in this instance had the fortune element of being on relative flat sea bottom. An anomaly would stick out like a sore thumb.
In the case that TIGHAR is investigating, I'm worried that the remains of an engine may be overlooked, because coral rubble may have cascaded on top and over it, give little or no topographical indication of what lies underneath.
Although, who is to say any wreckage (or all), has reached the bottom of the Drop-Off Zone? As previous ROV images show, this area is rather craggy and not smooth.