According to the pilot, as he approached the airport in Loman, Idaho, he requested a wind and weather PIREP. An unknown person replied on the CTAF to expect winds out of the west.
With the intent of landing on runway 2, he overflew the airfield and observed a light crosswind from the west.
He landed the Beech A36 on a 2,580′ turf surface.
The pilot recalled a shift in wind direction during landing.
The airspeed as he crossed the runway threshold was about 90 knots, and the airspeed “increased dramatically” during the landing flare and touchdown.
The pilot applied the brakes, however the airplane overran the departure end of the runway and hit a tree. The airplane sustained substantial damage to the engine mounts and the fuselage.
According to the pilot, witnesses to the accident recalled that the airplane landed in variable wind conditions and touched down with a 20- to 30-knot tailwind.
The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.
Probable cause: The pilot’s inadequate compensation for a tailwind, which resulted in a runway overrun.
NTSB Identification: GAA17CA497
This August 2017 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
This pilot was way to fast for any.approach to a 2500′ runway and should have done a go around anyway. My Bonanza experience would tell me to try again. Recheck wind conditions.
Wind speed isn’t constant but decreases logarithmically with altitude down to almost zero on the ground.
Let’s assume a windspeed of 20 knots measured at 30 feet AGL. The windspeed will increase to 30 knots at 100 feet and decrease to 6 knots at 10 feet.
The pilot stated an airspeed on final approach of 90 knots. Let’s assume he took a look at his ASI at an
altitude of 30 feet AGL.
According to the windspeed of 20 knots his groundspeed can be estimated to 110 knots.
At 10 feet AGL, however, the tailwind diminishes to just 6 knots which in turn INCREASES the aircraft’s airspeed by 14 knots to noticeable 104 knots.
In order to slow down the aircraft to some 60 knots at touchdown you can imagine that the airplane consumed quite a portion of the runway.
The pilot was not incompetent to judge the windspeed nor is he lying. He just was not experienced in downwind landings (read chapter 15 at “Perfect Piloting made easy”).
Come to my part of Nevada (and elsewhere I have flown). That ain’t happening.
An increase in tailwind will not result in an increase in airspeed.
An increase in groundspeed, maybe…?
True.
He admitted to having 90 knots airspeed crossing the threshold. That, on top of any tailwind beyond 10 knots at a 2500’ grass runway, even if dry, is usually a prescription for the result he experienced.
At least the grass won’t flatspot the tires with heavy braking…(eyeroll).
The tailwind DECREASES with lower altitude. The aircraft, however, maintains its groundspeed due to its inertia. So, the airspeed INCREASES.
Viktor: let me see if I’ve got this right:
If you’re maintaining 100 knots on final in a twenty knot tail wind and the tailwind suddenly decreases to zero, you’re saying that your airspeed will increase to 120 knots due to inertia…?
Can’t wait to hear the response. I’m containing my inertia in anticipation.
“The airspeed as he crossed the runway threshold was about 90 knots,…”
Way too fast in a Bonanza. Plus, grass if wet, makes for a slick surface.
Pilot observed a light crosswind from the West. Then a witness says touched down with a 20- to 30-knot tailwind The pilot is either too incompetent to judge wind speed or is lying.