ERAU Arrow crash preliminary report
04-17-2018, 05:43 PM
#11
Gets Weekends Off
Joined APC: Feb 2010
Posts: 2,276
Originally Posted by Blackhawk
I’ll be the jerk to say it.
I hope this accident weighs heavily on every ERAU student and CFI who ever did unauthorized aerobatics in one of these airplanes.
I hope this accident weighs heavily on every ERAU student and CFI who ever did unauthorized aerobatics in one of these airplanes.
04-17-2018, 06:10 PM
#12
In a land of unicorns
Joined APC: Apr 2014
Position: Whale FO
Posts: 6,454
Overload fractures due to excess G's in an Arrow happen further out the wingspan. If you snap a wing on an Arrow (According to Piper, it happens at 163.7% of design limit load which is around 7G) it fails at approx. 40% span.
If this damage was caused by heavy loads that were within the design envelope, that's a serious design flaw in itself.
So I'd imagine if the fatigue crack was caused by constant abuse, it would have been in a different location (assuming that the failure point is where the highest stress also is during excessive G maneuvering).
If this damage was caused by heavy loads that were within the design envelope, that's a serious design flaw in itself.
So I'd imagine if the fatigue crack was caused by constant abuse, it would have been in a different location (assuming that the failure point is where the highest stress also is during excessive G maneuvering).
04-18-2018, 02:38 AM
#14
All is fine at .79
Joined APC: Sep 2016
Position: Paahlot
Posts: 4,082
It’s not that difficult to roll or loop in a trainer. Depending on the airplane and the proficiency of the pilot the proper execution and if not the recovery may be very difficult.
No airplane I know off came apart during a spin. They do come apart in a botched recovery.
Considering a plane used for CPL Training does a lot of landings that plane may have had 25000+ landings including its share of unreported hard landings.
No airplane I know off came apart during a spin. They do come apart in a botched recovery.
Considering a plane used for CPL Training does a lot of landings that plane may have had 25000+ landings including its share of unreported hard landings.
04-18-2018, 04:21 PM
#15
Day puke
Joined APC: Feb 2006
Position: Out.
Posts: 3,865
Originally Posted by dera
Overload fractures due to excess G's in an Arrow happen further out the wingspan. If you snap a wing on an Arrow (According to Piper, it happens at 163.7% of design limit load which is around 7G) it fails at approx. 40% span.
If this damage was caused by heavy loads that were within the design envelope, that's a serious design flaw in itself.
So I'd imagine if the fatigue crack was caused by constant abuse, it would have been in a different location (assuming that the failure point is where the highest stress also is during excessive G maneuvering).
If this damage was caused by heavy loads that were within the design envelope, that's a serious design flaw in itself.
So I'd imagine if the fatigue crack was caused by constant abuse, it would have been in a different location (assuming that the failure point is where the highest stress also is during excessive G maneuvering).
04-19-2018, 10:29 AM
#16
Gets Weekends Off
Joined APC: Mar 2005
Posts: 1,888
Originally Posted by TiredSoul
It’s not that difficult to roll or loop in a trainer. Depending on the airplane and the proficiency of the pilot the proper execution and if not the recovery may be very difficult.
No airplane I know off came apart during a spin. They do come apart in a botched recovery.
Considering a plane used for CPL Training does a lot of landings that plane may have had 25000+ landings including its share of unreported hard landings.
No airplane I know off came apart during a spin. They do come apart in a botched recovery.
Considering a plane used for CPL Training does a lot of landings that plane may have had 25000+ landings including its share of unreported hard landings.
This was not a very old airplane by any stretch of the imagination and, according to the preliminary report, no sign of corrosion.
04-19-2018, 10:31 AM
#17
Gets Weekends Off
Joined APC: Mar 2005
Posts: 1,888
Originally Posted by 2StgTurbine
I have seen some stupid stuff at a college flight school, but I have never seen or heard of CFIs or students routinely doing aerobatic maneuvers in an Arrow. Aerobatics are actually difficult to do in a trainer, so most of the pilots dumb enough to do that wouldn't have the skill to perform any maneuver more complicated than an 80 degree bank.
04-19-2018, 10:37 AM
#18
Gets Weekends Off
Joined APC: Mar 2005
Posts: 1,888
My emphasis.
https://app.ntsb.gov/pdfgenerator/Re...relim&IType=FA
" Preliminary examination of the left wing main spar revealed that more than 80% of the lower spar cap and portions of the forward and aft spar web doublers exhibited fracture features consistent with metal fatigue (see figure 1).The remainder of the lower spar cap, spar web doublers, and upper spar cap displayed fracture features consistent with overstress fracture. The fatigue features originated at or near the outboard forward wing spar attachment bolt hole (see figure 2). None of the surfaces exhibited visible evidence of corrosion or other preexisting damage. The right wing also exhibited fatigue cracks in the lower spar cap at the same hole location extending up to 0.047-inch deep."
https://app.ntsb.gov/pdfgenerator/Re...relim&IType=FA
" Preliminary examination of the left wing main spar revealed that more than 80% of the lower spar cap and portions of the forward and aft spar web doublers exhibited fracture features consistent with metal fatigue (see figure 1).The remainder of the lower spar cap, spar web doublers, and upper spar cap displayed fracture features consistent with overstress fracture. The fatigue features originated at or near the outboard forward wing spar attachment bolt hole (see figure 2). None of the surfaces exhibited visible evidence of corrosion or other preexisting damage. The right wing also exhibited fatigue cracks in the lower spar cap at the same hole location extending up to 0.047-inch deep."
04-19-2018, 12:13 PM
#19
All is fine at .79
Joined APC: Sep 2016
Position: Paahlot
Posts: 4,082
Would a couple of high speed ( > Vne) dives (low passes) sufficiently weaken the wing.
I was glad when the owner of the flightschool I worked for switched to a whole new fleet.
I knew and flew every airplane from zero hours, hired the CFI’s that flew them and was very friendly with our Head of MX.
I knew what was wrong with each airplane and how it was repaired.
We at one point considered data loggers ( altitude & airspeed).
I was glad when the owner of the flightschool I worked for switched to a whole new fleet.
I knew and flew every airplane from zero hours, hired the CFI’s that flew them and was very friendly with our Head of MX.
I knew what was wrong with each airplane and how it was repaired.
We at one point considered data loggers ( altitude & airspeed).
04-19-2018, 12:49 PM
#20
Gets Weekends Off
Joined APC: Mar 2005
Posts: 1,888
Originally Posted by TiredSoul
Would a couple of high speed ( > Vne) dives (low passes) sufficiently weaken the wing.
I was glad when the owner of the flightschool I worked for switched to a whole new fleet.
I knew and flew every airplane from zero hours, hired the CFI’s that flew them and was very friendly with our Head of MX.
I knew what was wrong with each airplane and how it was repaired.
We at one point considered data loggers ( altitude & airspeed).
I was glad when the owner of the flightschool I worked for switched to a whole new fleet.
I knew and flew every airplane from zero hours, hired the CFI’s that flew them and was very friendly with our Head of MX.
I knew what was wrong with each airplane and how it was repaired.
We at one point considered data loggers ( altitude & airspeed).
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