cdillard

Hello. I have a question that involves the plane crash of a friend 35 years ago in Butler, Tennessee. Here is a transcript from FAA of the crash:

"3 KILLED BUTLER TN 1975-12-25, AIRFRAME FAILURE-IN FLIGHT; PILOT INDUCED; MTN RIDGE IN AREA OF ACDNT APRX 5700FT MSL.WINGS,TAIL SECTION SEPARATED PRIOR TO IMPACT."

Can someone provide a scenario/insight of what "AIRFRAME FAILURE-IN FLIGHT" means? Also, the relevance of "MSL.WINGS,TAIL SECTION SEPARATED PRIOR TO IMPACT."

The pilot was approaching an airport in the eastern Tennessee mountains and crashed.

Thanks for any insight you can provide.

iaflyer

It's very hard to do any analysis with the full accident report. The sentence "AIRFRAME FAILURE-IN FLIGHT" means that the airplane broke into pieces prior to impacting the ground.

The accidents that I've read about with that happening, the cause usually is flying into a thunderstorm, some sort of disorientation of the pilot so the pilot put the airplane into a high-G maneuver and the wing/tail broke off because it was overstressed. Also, it could be a mechanical failure where an autopilot failed, the pilot didn't recognize it in time. Or, it could be severe turbulence in the area and that overstressed the airframe.

These are just some of the possible reasons, an accident can have many causes. It is not necessarily one event or cause that would cause the accident.

ps. After adding the section in the next post, it looks like the pilot made a serious error: flying into instrument conditions that he was not rated for.

iaflyer

Here's the whole report, as it were from the NTSB database:

----------------------------------------------------------------------------------------------------------------------------
FILE DATE LOCATION AIRCRAFT DATA INJURIES FLIGHT PILOT DATA
F S M/N PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-4060 75/12/25 BUTLER,TN BELLANCA 17-31 CR- 1 0 0 NONCOMMERCIAL PRIVATE, AGE 66, 2596
TIME - 1403 N14707 PX- 3 0 0 PLEASURE/PERSONAL TRANSP TOTAL HOURS, 30 IN TYPE,
DAMAGE-DESTROYED OT- 0 0 0 NOT INSTRUMENT RATED.
DEPARTURE POINT INTENDED DESTINATION
CLINTON,MD TRI-CITY,TN
TYPE OF ACCIDENT PHASE OF OPERATION
AIRFRAME FAILURE: IN FLIGHT IN FLIGHT: UNCONTROLLED DESCENT
PROBABLE CAUSE(S)
PILOT IN COMMAND - CONTINUED VFR FLIGHT INTO ADVERSE WEATHER CONDITIONS
PILOT IN COMMAND - SPATIAL DISORIENTATION
PILOT IN COMMAND - EXCEEDED DESIGNED STRESS LIMITS OF AIRCRAFT
FACTOR(S)
WEATHER - LOW CEILING
MISCELLANEOUS ACTS,CONDITIONS - OVERLOAD FAILURE
MISCELLANEOUS ACTS,CONDITIONS - SEPARATION IN FLIGHT
WEATHER BRIEFING - BRIEFED BY FLIGHT SERVICE PERSONNEL, BY PHONE
WEATHER FORECAST - FORECAST SUBSTANTIALLY CORRECT
SKY CONDITION CEILING AT ACCIDENT SITE
OVERCAST 5000
VISIBILITY AT ACCIDENT SITE PRECIPITATION AT ACCIDENT SITE
5 OR OVER(UNLIMITED) DRIZZLE
OBSTRUCTIONS TO VISION AT ACCIDENT SITE TEMPERATURE-F
NONE 42
TYPE OF WEATHER CONDITIONS TYPE OF FLIGHT PLAN
VFR NONE
REMARKS- MTN RIDGE IN AREA OF ACDNT APRX 5700FT MSL.WINGS,TAIL SECTION SEPD PRIOR TO IMPACT.

USMCFLYR

Simply put it means the aircraft came apart in flight either due to pilot action or inaction by the pilot which led to the mishap (hence pilot induced). MSL means 'Mean Sea Level' - a type of altitude.

Sorry to her about your friend.
Did you get the above infomration from the NTSB database?
Here is a little more information:
IAD76AI044

USMCFLYR

iah beat me to it

Rhino Driver

The MSL goes with the 5700Ft. MSL is mean sea level, or altitude above sea level, and has no relevance to the rest of the quote.

As for the accident, hard to tell. The above poster shed light on many of the most probable causes. Were there thunderstorms in the area?

Sorry for your loss.

Ps: After reading IAD76AI044, the report sheds some light on things. The PIC was not instrument rated and flew into adverse weather conditions. My short analysis is that your friend probably became disoriented at altitude. Spacial disorientation is a primary factor in many general aviation accidents. When this occurs, your brain is telling your body one thing, based on what it perceives, but your instruments are showing you something else. When a pilot is not instrument rated, or has low time, this is very disorienting. This is exactly what happened to JFK junior a few years back.

When you haven't had adequate training, your instinct is to follow what your brain is telling you. When flying in adverse weather, even though you may be in straight and level flight (and your instruments are telling you that the aircraft is straight and level), your body may start to feel as if you are climbing, descending, turning, or a combination of all of these. If you haven't had adequate training, you may follow those cues and try to correct what your brain is feeling. This actually takes an aircraft that is straight and level and puts it into some other orientation. When it gets out of control, it's very easy for the aircraft to depart flight, or to exceed the design structural limits of the aircraft, resulting in "WINGS,TAIL SECTION SEPARATED PRIOR TO IMPACT."

I hope this may help you understand the situation a little bit more, and again, sorry about your friend.

cdillard

Thanks for the NTSB report. Some friends were asking about the cause of the crash and your responses have shed light on that question.

rickair7777

As others have said thunderstorms might have been involved but if the in-flight breakup was caused by the thunderstorm itself, the probable cause would have been something like "pilot continued flight into area of thunderstorm activity".

"Pilot Induced" in this case means that the investigators believe that the pilot became disoriented and placed the aircraft in an abnormal attitude, and then overstressed the control surfaces in an attempt to recover.

This is, unfortunately, a fairly common scenario in general aviation. Since the pilot did not have an instrument rating, and flew into IMC (Instrument Meteorological Conditions, ie very low visibility) this is a likely scenario. This could have been clouds with or without thunderstorms. Thunderstorms would have made the problem worse, as the turbulence would have compounded an attitude control problem but the weather report does not mention thunderstorms (might not have been 100% accurate). It is also possible for this to occur on a dark night, even without the presence of visible moisture (that's what happened to JFK junior). This could also happen to a qualified instrument rated pilot if he suffered a failure of critical flight instruments.

The industry term for this scenario is "graveyard spiral". General aviation has come a long way since the 1970's in educating pilots about the risks involved for non-instrument pilots in adverse weather. Unfortunately these were lessons learned the hard way, by too many good folks.

CaptainCarl

REMARKS- MTN RIDGE IN AREA OF ACDNT APRX 5700FT MSL.WINGS,TAIL SECTION SEPD PRIOR TO IMPACT.

Translation: Remarks - Mountain ridge in area of the accident. Highest approximate elevation of said mountain ridge is 5,700 feet above mean sea level (MSL). The wings and tail section separated from the aircraft prior to impact.

aviatorsneah

Without reading anything else on it (which back then there wasn't too much to these reports), i'd say the flight could have been IMC on an approach, the pilot got disoriented, lost control, and then when a mountainside came into view, he overstressed the airplane trying to recover. This resulted in the inflight breakup. Again, not saying this is what happened, but whenever I've read other NTSB reports involving an inflight breakup on an approach, it's during IMC.

edit: ah sorry didn't read the whole thread....inadvertent flight into IMC, not on an approach. but yeah i agree with everyone else's responses.

shame this happened on xmas day...

SKYKN6

FYI - In general the weak part ot a small airplane is the tail section. If it fails due to loads(thunderstorm/ pilot induced) the aircraft pitches nose down and breaks off the wings downward. This is easy to tell from the crash site. An upward failure of a wing would lead an investigator to inspect for mechanical or fatigue failure of the structure. With the indicated forecast it seems like the previous comments fall in line.