Galloping Ghost report

John Baker

Final Approach
Joined
Oct 4, 2008
Messages
7,471
Location
San Diego, California
Display Name

Display name:
John Baker
To ensure that this news release is delivered to your inbox, add
NTSB_NEWS@LISTSERV.NTSB.GOV to your address book.
NATIONAL TRANSPORTATION SAFETY BOARD NEWS RELEASE

An independent federal agency
DETERIORATED PARTS ALLOWED FLUTTER WHICH LED TO FATAL CRASH AT 2011 RENO AIR RACES
August 27, 2012
WASHINGTON – The National Transportation Safety Board determined today that deteriorated locknut inserts found in the highly modified North American P-51D airplane that crashed during the 2011 National Championship Air Races in Reno, Nevada, allowed the trim tab attachment screws to become loose, and even initiated fatigue cracking in one screw. This condition, which resulted in reduced stiffness in the elevator trim system, ultimately led to aerodynamic flutter at racing speed that broke the trim tab linkages, resulting in a loss of controllability and the eventual crash.

On September 16, 2011, as the experimental single-seat P-51D airplane “The Galloping Ghost,” traveling about 445 knots, or 512 mph, in the third lap of the six-lap race, passed pylon 8, it experienced a left-roll upset and high-G pitch up. During the upset sequence, the airplane’s vertical acceleration peaked at 17.3 G, causing incapacitation of the pilot. Seconds later, a section of the left elevator trim tab separated in flight. The airplane descended and impacted the ramp in the spectator box seating area, killing the pilot and 10 spectators and injuring more than 60 others.

“In Reno, the fine line between observing risk and being impacted by the consequences when something goes wrong was crossed,” said NTSB Chairman Deborah A. P. Hersman. “The pilots understood the risks they assumed; the spectators assumed their safety had been assessed and addressed.”

Contributing to the accident were the undocumented and untested major modifications made to the airplane, as well as the pilot’s operation of the airplane in the unique air racing environment without adequate flight testing.

The nearly 70-year-old airplane had undergone numerous undocumented modifications. The modifications, designed to increase speed, included shortening of the wings, installation of a boil-off cooling system for the engine, increasing the elevator counterweights, modification of the pitch trim system, and changing the incidence of the horizontal and vertical stabilizers.

Although the Federal Aviation Administration required that a flight standards district office be notified in writing of any major changes made to The Galloping Ghost before it could be flown, investigators could find no records that such notifications were made except for the installation of the boil-off cooling system. The undocumented major modifications were identified through wreckage examinations, photographic evidence, and interviews with ground crewmembers.

In April, while the investigation was ongoing and after the NTSB’s investigative hearing in January on air race and air show safety, the NTSB issued 10 safety recommendations to the Reno Air Racing Association, the National Air racing Group Unlimited Division, and the FAA. These recommendations addressed:

• requiring engineering evaluations for aircraft with major modifications;
• raising the level of safety for spectators and personnel near the race course;
• improving FAA guidance for air race and course design;
• providing race pilots with high-G training and evaluating the feasibility of G-suit requirements for race pilots; and
• tracking the resolution of race aircraft discrepancies identified during prerace technical inspections.

Although no additional safety recommendations were issued today, the Board reclassified nine existing recommendations as described below:

• Eligibility Requirements for Aircraft with Major Modifications – recommendations A 12 9 and A-12-13 classified “Open—Acceptable Response”

• Prerace Technical Inspection Discrepancy Tracking – recommendation A 12 10, classified “Closed—Acceptable Action”

• Spectator Safety – recommendations A 12 14 and 15, classified “Closed—Acceptable Action”

• High G Training, G-Suit Feasibility for Pilots – recommendations A 12 11, -12, -16, and -17, classified “Closed—Acceptable Action”

A tenth safety recommendation, issued to the FAA, which addressed air race and course design guidance was reclassified as “Open—Acceptable Response” on July 25, 2012.

“It’s good news for the air races that so many of our recommendations have been addressed,” said Chairman Hersman. “We will continue to push for the full implementation of all of our safety recommendations.”

A synopsis of the NTSB report, including the probable cause and a complete list of the reclassified safety recommendations, is available at: http://www.ntsb.gov/news/events/2012/reno_nv/index.html.

Other information and previous press releases related to the Reno Air Races investigation:

• NTSB opens docket on Reno Air Races crash
http://www.ntsb.gov/news/2012/120821b.html
• NTSB to issue safety recommendations on air races and provide investigative update on 2011 crash at the Reno Air Races http://www.ntsb.gov/news/2012/120405.html
• NTSB January 10, 2012, hearing on Air Race and Air Show Safety http://www.ntsb.gov/news/events/2012/air_show/index.html
• NTSB Provides Investigative Update and Issues Recommendations to Increase Safety at Air Races
http://www.ntsb.gov/news/2012/120410.html

#NTSB#

blank.gif
Contact Information
Office of Public Affairs
490 L'Enfant Plaza, SW
Washington, DC 20594


(202) 314-6100
terry.williams@ntsb.gov

============================================

I copied and pasted this just as I recieved it.

-John
 
Last edited:
wow, 17.3 g's and the wings didn't fall off
 
All those recommendations, and it comes down to this:

DO NOT REUSE LOCK NUTS ON FLIGHT-CRITICAL SYSTEMS

And also, only use them in appropriate places. I know of another relatively recent flight control failure in an aircraft (fortunately, a safe landing was accomplished) that was caused by failure of a reused lock nut.

Here is a helpful guide:

Recommendations for use per FAA AC43.13-1B Acceptable Methods and Practices:

Elastic lock nuts are not to be installed in areas exceeding 250 degrees F.
Do not reuse elastic lock nuts if the nut cannot meet the minimum prevailing torque values shown in the chart
Do not use self-locking nuts on parts subject to rotation
Do not use self-locking nuts where the loose nut, bolt, or washer may fall or be drawn into the engine air intake scoop.
Do not use self-locking nuts to attach access panels, doors, or any parts that are routinely disassembled before or after each flight.


Jeff
 
Sad event. Operating in extreme conditions with old parts is never a good idea. Failure to replace the locknut inserts, which surely must have been one of the least costly parts on the aircraft, is inexplicable to me. :dunno: For the want of a nail.....
 
What amount of g force causes internal damage....or what is the likely first internal damage? I bet NASA knows. Maybe it's a simple internet search to find the answer.

An article about Col. Stapp seemed to say that retinal hemes are the beginning tissue damage but I'll have to read the article a little more thoroughly. 30g's looks to be a basic limit dependng on how the g-force is applied (and it probably is variable per human). Loss of orientation and consciousness occurs way before that.
 
Last edited:
every type of airplane is going to have a different answer to that question. i just find it surprising that any type of plane could experience that level of loading and still remain in one piece.
 
Are we talking about a "Nylock" or "aircraft" nut here? I'm not an expert, but I can't believe a Reno race crew would re-use (or neglect) something like that on anything related to control surfaces. Even for normal flight, it seems like a bad idea.
Furthermore, I'm having trouble understanding why you'd use a nut like that at all in this case, rather than a castle nut with a pin or wire. Cotter pins or wire will deteriorate, too, but at least you can easily see what sort of shape they're in without removing them.
 
Interesting is the comment of numerous undocumented changes to the aircraft.

But it is amazing, that in all the debris, they were able to find the trim tab attach points and study the locknuts and screws. And to determine that a screw had internal failure.
 
those parts probably didn't make it to the fireball.
 
Are we talking about a "Nylock" or "aircraft" nut here? I'm not an expert, but I can't believe a Reno race crew would re-use (or neglect) something like that on anything related to control surfaces. Even for normal flight, it seems like a bad idea.
Furthermore, I'm having trouble understanding why you'd use a nut like that at all in this case, rather than a castle nut with a pin or wire. Cotter pins or wire will deteriorate, too, but at least you can easily see what sort of shape they're in without removing them.

The warriors I fly have a critical locknut Inspected every preflight on the stabilitator linkage. I would much rather have a cotter pin to look at
 
Interesting conclusions. I happened to be there that day for my first Reno air race ever, fortunately on the grand stand furthest away from the accident. I must admit, up until the point of the crash, it was THE best aviation event I had ever been to. I'm glad the show continues this year, but my GF (who was there with me last year) will never go back to it with me, so I probably won't be going again anytime soon. She has agreed however to keep going to non-race airshows though, like Oshkosh, which we'll do next year for the first time :yesnod:
 
She has agreed however to keep going to non-race airshows though, like Oshkosh, which we'll do next year for the first time :yesnod:

Just don't tell her the afternoon warbird reviews can go from a decent show to amateur hour in a heartbeat.

This year's radio calls from a flight lead of T-28s saying "Alert, Alert, oh **** RV's everywhere, Alert!" when two flights of differing types ended up in the same place at the same time, was chilling.

Frankly, they're damn lucky there wasn't a mid-air that afternoon.

The airshow "proper" is much better run.

And of course, don't stand near 18/36 when Jack Rousch is arriving... ;)
 
What amount of g force causes internal damage....or what is the likely first internal damage? I bet NASA knows. Maybe it's a simple internet search to find the answer.

An article about Col. Stapp seemed to say that retinal hemes are the beginning tissue damage but I'll have to read the article a little more thoroughly. 30g's looks to be a basic limit dependng on how the g-force is applied (and it probably is variable per human). Loss of orientation and consciousness occurs way before that.

50G is 50% fatalities with the Aorta tearing off first. 100G is 100% fatalities.
 
every type of airplane is going to have a different answer to that question. i just find it surprising that any type of plane could experience that level of loading and still remain in one piece.

Ever seen the wings on those racers? They clip the heck off of them.
 
yea i know the wings are short but thats still a lot of load.
 
All those recommendations, and it comes down to this:

DO NOT REUSE LOCK NUTS ON FLIGHT-CRITICAL SYSTEMS

And also, only use them in appropriate places. I know of another relatively recent flight control failure in an aircraft (fortunately, a safe landing was accomplished) that was caused by failure of a reused lock nut.

Here is a helpful guide:

Recommendations for use per FAA AC43.13-1B Acceptable Methods and Practices:

Elastic lock nuts are not to be installed in areas exceeding 250 degrees F.
Do not reuse elastic lock nuts if the nut cannot meet the minimum prevailing torque values shown in the chart
Do not use self-locking nuts on parts subject to rotation
Do not use self-locking nuts where the loose nut, bolt, or washer may fall or be drawn into the engine air intake scoop.
Do not use self-locking nuts to attach access panels, doors, or any parts that are routinely disassembled before or after each flight.


Jeff

Interesting that they say "Do not reuse" in one breath, then say "Replace when they do not meet torque specs" . More confusion for the uninitiated.

I was taught replace Nyloc nuts after 2 -3 uses. Seems to have worked so far. ;)
 
yea i know the wings are short but thats still a lot of load.
It also helps that it was flying at a lot lower weight than it was originally designed for with all the armor, weapons, radiator, etc. removed.
 
Last edited:
Back
Top