Prelim NTSB Report for Embry Riddle Arrow w/Structural Failure

[Hank]

5 hours ago, Hyett6420 said:

No because this was caused by corrosion not stess.  Stressing a wing wnt cause corrosion just stress

Failure was caused by corrosion in the cracks. But the cracks could have been caused by multiple overstress cycles. The NTSB will figure it out. Unlike the 737 fan failure, no one is calling for widespread Piper wing inspection, as this is apparently viewed as an isolated event not indicative of systemic design issues.

[AlexLev]

https://www.facebook.com/gold.standard.aviation.one/videos/1519540618154327/?hc_ref=ARRr2_LZkhmSTPt3zC4TRk1yCjfbynNULunyiXa0RG9wt1jgGebsJlArgXcWKBkTOmA&fref=nf

[aviatoreb]

3 hours ago, AlexLev said:

https://www.facebook.com/gold.standard.aviation.one/videos/1519540618154327/?hc_ref=ARRr2_LZkhmSTPt3zC4TRk1yCjfbynNULunyiXa0RG9wt1jgGebsJlArgXcWKBkTOmA&fref=nf

Holy moly!  What’s going on there?  Was that airplane flying recently like that?!!

[RLCarter]

4 hours ago, AlexLev said:

https://www.facebook.com/gold.standard.aviation.one/videos/1519540618154327/?hc_ref=ARRr2_LZkhmSTPt3zC4TRk1yCjfbynNULunyiXa0RG9wt1jgGebsJlArgXcWKBkTOmA&fref=nf

Saw that the other night....any idea how to get the video for the no-facebookers?

[Yooper Rocketman]

7 hours ago, M20Doc said:

I dislike the speculation that forums bring out, give a person a keyboard and they feel obligated to type on subjects they have little experience.  

I posted pictures of a Cherokee spar in my shop yesterday it tooks a few minutes to expose it for inspection.  The level of inspection required is the question.

In the picture on the NTSB report you can see the beach marks which show the progression of the crack.  

“Beach marks are macroscopic progression marks on a fatigue fracture or stress-corrosion cracking (SCC) surface that indicate successive positions of the advancing crack front. They take the form of crescent-shaped macroscopic marks on fatigue fractures representing positions of the crack propagation, radiating outward from one or more origins.

Beach marks are also known as clamshell marks, arrest marks or growth rings”

Clarence

Clarence,

In my business I’ve had to complete a ton a failure analysis (over 40 years worth).  I absolutely come unglued when one of my techs runs their mouth before proper and complete research is done.   Many times, once I’ve completed my research and determined the root cause of a failure, those techs want to completely forget how foolish they looked in talking before knowing all the facts.  A few of those and they now shut up until all facts are discovered and evidence is examined. A few now even enjoy the process and satisfaction of a result that is backed by facts.

Seems not too long ago I saw you post thoughts on a wing that MIGHT NOT need to be replaced.  I chuckled at the time, thinking why don’t people digress to those “in the know”, and making a mental note to self: “let’s see how this turns out”.  (+1 Clarence).

Needless to say you’ll look hard and long for any comments from me on situations where the REAL ANSWER can only be determined with much research and investigation.  Been there, done that.

Tom

[Hank]

1 hour ago, David Herman said:

That is just scary!!!

Really makes me glad that my wing isn't just bolted together!

[Guest]

That video would suggest the front wing par attach is broken or the bolt is missing.  This picture is from a straight wing, the taper wings are similar enough.  Item 10&11

Mooney also has a front spar fitting.

Clarence

Edited April 21, 2018 by M20Doc

[Guest tommy123]

I worked on that Braniff 747-100, N601BN. Boeing wanted to buy it for analysis, being the highest time 747 there was. Didn't offer enough money for it. That airplane had close to a100% dispatch rate. After Braniff went tu someone flew it for a while before being scrapped. It either flew dfw to London or DFW to Hawaii every day. 8 hour legs.

[Mark89114]

On April 21, 2018 at 9:54 AM, AlexLev said:

https://www.facebook.com/gold.standard.aviation.one/videos/1519540618154327/?hc_ref=ARRr2_LZkhmSTPt3zC4TRk1yCjfbynNULunyiXa0RG9wt1jgGebsJlArgXcWKBkTOmA&fref=nf

I read another forum posting that mentioned looked fake, the landing gear is supported by the wings and seems to move awfully easy with very little effort. Like the airplane fuselage is supported somehow.  

[RLCarter]

2 hours ago, Mark89114 said:

I read another forum posting that mentioned looked fake, the landing gear is supported by the wings and seems to move awfully easy with very little effort. Like the airplane fuselage is supported somehow.  

Maybe, it has been removed from FB

[thinwing]

On 4/19/2018 at 3:34 PM, M20Doc said:

The fracture line is through the outer 2 bolt holes on the lower spar cap.  Where do you see evidence of a repair in the picture posted in the NTSB report?  The opposite spar cap shares the start of the same fracture according to the NTSB report.  I doubt the same exact damage or repair was made to both wings at the exact same location.

There is clearly more to the story.

Clarence

I was going ask if inspection is accessible but you answered my question with that 140 photo...I would expect an AD over this

[steingar]

The only structural failures I've seen with Cherokees is when they flew into thunderstorms.  I can't imagine what they did to that poor thing.

[zaitcev]

On 4/17/2018 at 4:40 PM, AlexLev said:

An airplane manufactured in 2007 with metal fatigue on the spar, undetected at annual just 28 hours prior. Although, I don't know how extensive the 100 hour annuals are. Gives me a little bit if an unsettled feeling flying a 50-year old airframe...especially one that likes the yellow arc so much.

Your 50-year-old plane wasn't made from a cheap Chinese aluminum after a bankruptcy.

[carusoam]

Uneasy feelings are a good thing...

These feelings make you.

• ask more questions...
• Look into things further...
• Take your preflights a bit more seriously...
• Add a step to your written procedures...
• Discuss it on MS...
• avoid other’s mistakes of the past...
• Reminds you to say something when you see something...
• Do a new WnB calculation...
• Re-Do a T/O performance calc...

PP Thinking out loud... not a CFI.

Best regards,

-a-

 

 

 

[Yetti]

I happened to have the side panel off recently.   There is alot of boxes and supporting angled tubing around the cabin in the Mooney.

[MB65E]

What was the FB video? The firefighting C130 wing failure? 

-Matt

[AlexLev]

Additional info released by NTSB regarding crash: https://www.ntsb.gov/news/press-releases/Pages/NR20180515.aspx

[carusoam]

That report is stating clearly that the one plane had multiple signs of significant over stress.

They used an eddy current inspection system ECI to measure each of the cracks, both depth and width... and compared to several other similar planes that showed no cracks...

News like that helps arm your PPI checklist... not sure what you can do with that info as a renter of such planes...

Best regards,

-a-

[Parker_Woodruff]

 

19 hours ago, AlexLev said:

Additional info released by NTSB regarding crash: https://www.ntsb.gov/news/press-releases/Pages/NR20180515.aspx

Interesting update.

My first Mooney was an E-R trainer - 1990 M20J-AT.

I was the third owner - purchased it with ~6900 AFTT.  I think it was originally sold with 6400 hours.  I'm guessing that was probably 15,000-20,000 landings before I took it.  Clean airframe though...