Let’s start over - Mooney caravan incident

[bradp]

The previous thread had gotten off track a bit. 

Let’s Re-center the conversation in this forum. 

NTSB prelim out:

https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20190724X81016

 

On July 21, 2019, about 1000 central daylight time, a Mooney M20J airplane, N9201A, and a Mooney M20U, N197CV, collided in flight while flying in formation for a mass arrival at Wittman Regional Airport (KOSH), Oshkosh, Wisconsin. Both airplanes sustained minor damage. Neither pilot nor their passengers were injured. The personal flights were conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no Federal Aviation Administration (FAA) flight plan had been filed for either flight. Both airplanes departed Dane County Regional Airport - Truax Field (KMSN), Madison, Wisconsin, and were en route to KOSH.

According to the pilots of the two airplanes, they were flying in formation and were encountering turbulence related to wake vortices. The two airplanes were maneuvering to join the formation of another two-ship flight when the right wingtip of N9201A collided with the rudder of N197CV. Both airplanes landed without further incident and were unaware of the collision until after they landed.

[KSMooniac]

...and here we go!

Sent from my LG-US996 using Tapatalk

[Yetti]

"turbulence related to wake vortices "       http://www.aviation-history.com/theory/lam-flow.htm

[steingar]

What the pilots probably encountered was prop wash, which is to be expected flying in formation to Oshkosh.  I've hit it nearly every time I've flow in.  No excuse for what happened.

All that said, the Caravan leadership is responding intelligently, at least from what I've seen here.  A review of procedures to determine how to prevent it happening again.  I could ask no more, were I in a position to ask.

[0TreeLemur]

where's what's-his-name??

 

[mike_elliott]

3 minutes ago, 0TreeLemur said:

where's what's-his-name??

 

Right here

[jetdriven]

4 hours ago, Yetti said:

"turbulence related to wake vortices "       http://www.aviation-history.com/theory/lam-flow.htm

That somehow pushed the wingman ahead of the lead.  And caused him to forget a “not in sight” call. 

[Yetti]

So people keep telling me that I don't know anything about formation flying.  But the FAA keeps making me learn about Wake turbulence.  We know that they sink and they stick around if there is no wind.   below are the surface winds at Oshkosh during the time of the incident.   I guess it would be better if we could get the 3000 foot winds

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_90-23G.pdf

"Vertical Movement. Flight tests have shown that at higher altitude the vortices from large aircraft sink at a rate of several hundred feet per minute (fpm), slowing their descent and diminishing in strength with time and distance behind the wake-generating aircraft (see Figure 5, Descent of Vortices from Large Aircraft). Atmospheric turbulence hastens decay. Pilots should fly at or above the preceding aircraft’s flightpath, altering course as necessary, to avoid the area behind and below the generating aircraft. "

9:45 AM	70 F	37 F	31 %	NE	7 mph	0 mph	29.0 in	0.0 in	0.0 in	Partly Cloudy
10:45 AM	70 F	37 F	31 %	ENE	9 mph	0 mph	29.1 in	0.0 in	0.0 in	Partly Cloudy
11:45 AM	72 F	37 F	29 %	ENE	8 mph	0 mph	29.1 in	0.0 in	0.0 in	Partly Cloud

[bradp]

You certainly do catch "wake turbulence".  It's from a 3000 ish lb aircraft, so it's not the same as or have the same danger as following a Boeing (or a ford trimotor as was exemplified during this year's Oshkosh arrivals).  But that 3000 lb aircraft is 10-15 seconds ahead.  Say the wake descends at 300 fpm for conjecture's sake.  In 15 seconds that's a 75ft ish descent.  I know I was hitting wake in the second "element" - it was characterized by some initial buffeting followed by roll tendency (you knew it was coming each time).  Almost everyone I spoke with encountered some low level wake turbulence.  We just took our formation a bit "wider" than if it was smooth air to give some extra buffer room.  Some of the elements behind us climbed 50-100 ft.  The lead element had "glass smooth" air, so we knew the bumps were due to wake.  Personally, I did not think for one minute that the wake vortices I experienced were associated with any increased risk beside giving a slightly wider berth since small roll inputs were needed to maintain station.   I imagine that the elements down the line were probably getting some wake from the element or two ahead of them, but further ahead wake vortices had probably already sunk below.

[Hank]

8 hours ago, steingar said:

What the pilots probably encountered was prop wash, which is to be expected flying in formation to Oshkosh.  I've hit it nearly every time I've flow in.  No excuse for what happened.

All that said, the Caravan leadership is responding intelligently, at least from what I've seen here.  A review of procedures to determine how to prevent it happening again.  I could ask no more, were I in a position to ask.

But no one is in that position, except for the investigators . . . . . Even though we all ask about and discuss aviation incidents / accidents in all makes, brands and countries. Except for this incident . . . .

[Guest]

I didn’t see the damage, but this prop wash would leave quite a dent at 120 kts if you ran into it.

Clarence

[steingar]

9 hours ago, Hank said:

But no one is in that position, except for the investigators . . . . . Even though we all ask about and discuss aviation incidents / accidents in all makes, brands and countries. Except for this incident . . . .

Many specifics of the accident have been posted.  I think the principals would be more forthcoming, but there are issues with repairs and the FAA.  Like I said, who did what to whom isn't important.  What is important is that the organization respond intelligently, which I hope they have.

Edited August 22, 2019 by steingar

[Yetti]

here's one thing I know from growing up racing sailboats.  There is dirty air coming off the just slightly downwind and aft of another boat's sail going through the air.   You don't want to be there because it is slower than being in clean air.   So I think we can agree there was disturbed air, the question would be does a 2700lb laminar flow wing create enough wake vortices to cause a safety of flight issue.  or was it the prop creating disturbed air.  Then does the same vortices create a safety of formation issue.  I mean the official people who the only ones who know have already listed it in the official statement that could be revised.

[bradp]

Wake turbulence was perhaps a factor but not a root cause. 

[Guest]

If wake turbulence or prop wash were the cause, why has it taken all these years for this minor incident to occur?

Clarence

[jetdriven]

Interesting. Wake turbulence from the same type of aircraft somehow throws the wingman 200-300' forward and into the path of the lead?  Come on.....

Edited August 23, 2019 by jetdriven

[Yetti]

In RCA and my understanding of Navy flight investigation you put all possible causes on the table.   Then disprove any and all.   Then you are left with the most probable causes.  And a list of possible unproven options that is available if  someone were to say "What about wake turbulence or prop wash"

So next theory?

[Hank]

3 hours ago, jetdriven said:

Interesting. Wake turbulence from the same type of aircraft somehow throws the wingman 200-300' forward and into the path of the lead?  Come on.....

 

58 minutes ago, Yetti said:

In RCA and my understanding of Navy flight investigation you put all possible causes on the table.   Then disprove any and all.   Then you are left with the most probable causes.  And a list of possible unproven options that is available if  someone were to say "What about wake turbulence or prop wash"

So next theory?

Inadvertent activation of tractor beam?

[thinwing]

On 8/22/2019 at 4:04 AM, M20Doc said:

I didn’t see the damage, but this prop wash would leave quite a dent at 120 kts if you ran into it.

Clarence

Like this?

[GeeBee]

Some people are not going to like what I say, but I'll say it anyway.

This formation arrival stuff as presently constituted is just plain nuts.

I don't fly formation with people I barely know and have not trained VIGOROUSLY  with and I mean not briefings, not flying formation with someone else, not "I know the ground rules". I mean hours of practice. Sure they do it in the military after lots of training, very high standardization and lets face it a Mooney is not maneuverable like an F-16.

 

 

 

[steingar]

1 hour ago, GeeBee said:

Some people are not going to like what I say, but I'll say it anyway.

This formation arrival stuff as presently constituted is just plain nuts.

I don't fly formation with people I barely know and have not trained VIGOROUSLY  with and I mean not briefings, not flying formation with someone else, not "I know the ground rules". I mean hours of practice. Sure they do it in the military after lots of training, very high standardization and lets face it a Mooney is not maneuverable like an F-16.

The EAA has been doing this for their fly-ins for decades.  I've been going 20 years myself.  Tens of thousands of pilots in every sort of airplane, most pilots untrained in any kind of formation flight, many haven't even read the damn NOTAM.  And in all that time they've had the same number of midairs as the Mooney Caravan has flying 50 aircraft a year for a decade.

 

You tell me who's nuts.

[GeeBee]

Nothing wrong with the Fly-In. Heck I am President of my local chapter. The issue is risk and exposure. The risk is high, the exposure level is low. Once a year. The outcome? Two airplanes that collide with catastrophic results. Graph that on the risk management scale. 

[steingar]

2 minutes ago, GeeBee said:

Nothing wrong with the Fly-In. Heck I am President of my local chapter. The issue is risk and exposure. The risk is high, the exposure level is low. Once a year. The outcome? Two airplanes that collide with catastrophic results. Graph that on the risk management scale. 

Except that it hasn't happened.  You're more likely to get into a midair at your local pancake breakfast.

[thinwing]

31 minutes ago, GeeBee said:

Nothing wrong with the Fly-In. Heck I am President of my local chapter. The issue is risk and exposure. The risk is high, the exposure level is low. Once a year. The outcome? Two airplanes that collide with catastrophic results. Graph that on the risk management scale. 

Our local chapter as embraced formation flying in their RV s to the extent they have formed an air show performers group.They also fly “missing man” formations at military funerals locally.They may be “nuts”but I’m impressed with their skill and professionalism 

[thinwing]

44 minutes ago, GeeBee said:

Nothing wrong with the Fly-In. Heck I am President of my local chapter. The issue is risk and exposure. The risk is high, the exposure level is low. Once a year. The outcome? Two airplanes that collide with catastrophic results. Graph that on the risk management scale. 

What was the catastrophic result?