Official Probable Cause Report Spreads Blame

The NTSB report blames the pilots in both aircraft and the tower controllers in a mid-air last year between a C-150 and a de Havilland Beaver (file photos of types below). As ANN reported, the two aircraft collided as they were approaching the pattern at Renton, WA last August. Following the collision, the Beaver landed with substantial damage reporting five injured. Two aboard the C-150 were killed when it spiraled out of control.

The report says the C-150 was cleared by a tower controller -- in training and supervised -- to enter downwind for Rwy 33 via the forty-five. The controller also advised the C-150's pilot of "...traffic ahead and to your right, one thousand six hundred, turning southbound, type unknown." The Cessna pilot did not respond to the advisory.

Another Beaver (not the accident plane) approaching the airport was cleared to enter downwind for Rwy 33 and advised the C-150 was passing behind him, no factor.

Around 20 seconds later, the accident Beaver's pilot reported inbound and was notified of traffic (the accident Cessna) "...twelve o'clock, two miles, a Cessna, one thousand three hundred southbound." The controller then cleared the Beaver to enter downwind on the forty-five following the Cessna.

When the controller asked the accident Beaver's pilot if he had the traffic in sight, the pilot responded "...we've got an aircraft on downwind ahead of us in sight." The controller instructed him to "...follow that aircraft."

At that point, three aircraft were approaching the downwind for Rwy 33 on the forty-five. When the first Beaver reported entering downwind he was cleared to land on the water adjacent Rwy 33. The controller then cleared the Cessna to proceed direct to the downwind.

Now we have the C-150 southbound on downwind to land on Rwy 33, and a Beaver (not the accident plane) also on downwind, ahead and to the outside of the Cessna, landing on the water. The accident Beaver is about to enter downwind on the forty-five.

When the pilot of the Cessna reported the Beaver to his right approaching downwind in sight, the controller asked the approaching beaver if he had the Cessna in sight. The Beaver's pilot replied, "…affirmative. We have the aircraft on base."

At this point the controller asked the accident Beaver if he had the traffic passing under him (the accident Cessna) in sight. The accident Beaver's pilot answered "...ah yeah, base to final landing on the water."

The Cessna's right wing glanced off the Beaver's left float before impacting the inboard portion of the right float. The Beaver's prop penetrated the top outboard section of the Cessna's right wing before impacting its fuselage rendering it uncontrollable.

In his statement following to the NTSB, the accident Beaver's pilot said, "The Beaver ahead of me was given clearance to proceed as requested. I informed the tower that I had the traffic ahead and on downwind in sight and was told to follow him."

The NTSB officially blames the accident on the failure of the Beaver pilot to understand air traffic advisory information and the failure of the Cessna pilot to maintain visual separation, resulting in a midair collision. A factor contributing to the accident was the inadequate traffic advisory information provided by air traffic controllers.

FMI: www.ntsb.gov