How accurate are NTSB reports?

FloridaPilot

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Hello,


I was going through the NTSB reports on aircraft accidents for this year and quite a few of them the NTSB person did not show up to fully investigate:


So I was wondering how accurate can these reports be?



Thanks!
 
Hello,


I was going through the NTSB reports on aircraft accidents for this year and quite a few of them the NTSB person did not show up to fully investigate:


So I was wondering how accurate can these reports be?



Thanks!

I worked with a NTSB gal for 3 days.. In the beginning I thought she was over the top competent...

2 years later the report came out......

Color me NOT impressed.... The spelling errors were very telling on how sharp she ISN'T.......:(:(


http://dms.ntsb.gov/public/57000-57499/57405/575420.pdf
 
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I think they often do a great job of finding a cause out of a pile of parts.

But you'll never really know what happened unless you were there. Take the following crash: Without video, it probably would have been the old "pilot's failure to maintain airspeed resulting in a stall." But with the video, they determined that a wind shift was the main cause.

https://www.youtube.com/watch?v=jjRPY4_XKy0
 
Sometimes at the end of the day their conclusions are based on subjective factors, and you'll see phrases like pilot fatigue, pilot distraction, etc. that may or may not be correct.

In the case Ben mentions, I was appalled at the amateurish manner in which the report was done. It read like a book report by a high school sophomore.
 
I know of one that is factually incorrect... for sure. The FAA did the investigation, though and an NTSB person only took that inspector's apparent word for it.
 
My wifes twin sister worked for the NTSB for several years. In the course of that time I got to know the people in her office. Even got an hour in her bosses Bell 47.:)

I think that most of the investigators are competent, but for most accidents are not really allotted enough time to do a thorough investigation. Only the high profile accidents get that level of attention devoted to them.

My $0.02,
 
They are humans and government employees. As such, some take their responsibility much more seriously than others. The quality of small GA accidents can vary significantly due to the personality of the investigator and amount of resources assigned.

The high profile accidents (121 and GA with celebrities) have teams of people involved and as a natural byproduct, the product is a higher quality.

You see things like dissenting opinions in some high profile cases. I don't think most GA accidents go to a vote.
 
They are humans and government employees. As such, some take their responsibility much more seriously than others. The quality of small GA accidents can vary significantly due to the personality of the investigator and amount of resources assigned.

The high profile accidents (121 and GA with celebrities) have teams of people involved and as a natural byproduct, the product is a higher quality.

You see things like dissenting opinions in some high profile cases. I don't think most GA accidents go to a vote.

I know of one that didn't even get passed around the office for peer review and checking for spelling errors...:rolleyes:....:mad:
 
Having been involved directly in one NTSB investigation, my opinion of them is very low. They seem only interested in publishing a "probable cause" rather than doing a thorough investigation........
 
The depth of the investigation depends on the accident, the people, the weather, the damage and a number of other factors. The NTSB's goal is to learn enough to get a handle on the types of issues that occur so it can make recommendations based on the trend of its probable cause findings. In some cases, it's going to be pretty minimal

We live in a society in which the need to assign blame and fault is so pervasive, it's sometimes difficult for to understand the existence of a government body that is not in the blame business. But that is essentially what the NTSB does in ts investigation capacity - one of the reasons the probable cause findings and conclusions are not admissible in litigation.
 
Thanks for the input!

I always thought, (In the past) that they're at least 90% accurate. Does insurance companies pressure them to provide an accurate analysis?
 
I had an engine failure in a Cessna 172 resulting in an off-airport landing. The NTSB report stated that the engine failure was due to unknown causes. Later, I heard from the FAA and the flight school owner that they actually discovered what had caused the engine to quit - it was a defective magneto switch. Evidently they never bothered to go back and amend the report. Because of this, I tend to read those reports with of touch of skepticism.
 
I had an engine failure in a Cessna 172 resulting in an off-airport landing. The NTSB report stated that the engine failure was due to unknown causes. Later, I heard from the FAA and the flight school owner that they actually discovered what had caused the engine to quit - it was a defective magneto switch. Evidently they never bothered to go back and amend the report. Because of this, I tend to read those reports with of touch of skepticism.
Not saying this was the situation in your case, but sometimes it is more about a different standard of proof than laziness (although I am sure that occurs in some cases as well).

The NTSB tends to have a lot of engineer/scientist types who look at things in a very statistical mindset. The FAA might see something as having a 85-90% likelihood of being the culprit, whereas a NTSB type would say that is not conclusive enough. I've discovered this sort of thinking in the defense test and evaluation world. We deal with a lot of PHDs who just don't think like I do...
 
Not saying this was the situation in your case, but sometimes it is more about a different standard of proof than laziness (although I am sure that occurs in some cases as well).

The NTSB tends to have a lot of engineer/scientist types who look at things in a very statistical mindset. The FAA might see something as having a 85-90% likelihood of being the culprit, whereas a NTSB type would say that is not conclusive enough. I've discovered this sort of thinking in the defense test and evaluation world. We deal with a lot of PHDs who just don't think like I do...
Shortly afterwards, the FAA issued an AD on the mag switches. I think that proved it as far as I was concerned.
 
Shortly afterwards, the FAA issued an AD on the mag switches. I think that proved it as far as I was concerned.
Like I said, I'm not saying you are wrong, just that sometimes, the NTSB types don't look at things the same way we do.
 
How does insurance companies determine the cause of the accident? Surely they need an accurate analysis!
 
I'm aware of one report of a crash in Harrison, AR that was a complete fabrication due to political pressure applied by a former congressman and his son who was the former head of the NTSB.

The pilot was a banker and a big supporter of dad...
 
Sometimes airplanes break. But the NTSB cant find any evidence of pre crash breaking. So they say its pilot error because it looks like a stall/spin/hit.

Remember it is "most probable cause". They dont claim its gospel truth. No one really knows for sure.
 
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I know of one, where I was a witness, misstated time of day by roughly 12 hours (night to day). I have always wondered if that was due to a NTSB mistake or by an outside force to save the airport or pilot's certificate since the airport was technically closed to night operations after a certain time. :\


Sent from my iPad using Tapatalk
 
Thanks for the input!

I always thought, (In the past) that they're at least 90% accurate. Does insurance companies pressure them to provide an accurate analysis?
The NTSB doesn't respond much to pressure except perhaps very strong political pressure.

The NTSB typically doesn't care what insurance companies, airlines, pilots, mechanics, etc think. It's own rules and policies allow for input by stakeholders. Those same rules provide that the stakeholder reps be the folks with operational knowledge, not the CEOs, and to toss them out if they try to spin the investigation.

Insurance companies will obviously use the analysis when making coverage decisions, and plaintiff lawyers will use them as part of their own decision whether or not to take a case. But beyond that, if there is a dispute, they'll have to spend the bucks on their own experts and their own accident analysis.
 
Thanks for the input!

I always thought, (In the past) that they're at least 90% accurate. Does insurance companies pressure them to provide an accurate analysis?
Nope. One of the accidents I know of was classified by the FAA guy as a handpropping accident, when the written reports by both the occupants said that it was a taxi incident... and they are telling the truth.
 
Sometimes airplanes break. But the NTSB cant find any evidence of pre crash breaking. So they say its pilot error because it looks like a stall/spin/hit.

Remember it is "most probable cause". They dont claim its gospel truth. No one really knows for sure.

Right.
 
that they're at least 90% accurate. Does insurance companies pressure them to provide an accurate analysis?
The premise of your question is wrong - as if under pressure they were able to deliver more 'accurate' analysis. Very often airplanes don't have any black boxes and like it was stated above the best they can do is come up with 'probable cause'. I think overall they could be 90% accurate, most accidents are just a tiresome repetition of what happened before and are not very interesting in terms of impact on safety - it is important for them to be right where it really matters, a good example is a crash of Sino Swearingen SJ30 prototype business jet in 2003 with test pilot aboard, this is a type of accident where they will put a lot of effort to get it right since implications for the industry are significant, they don't have unlimited budget they have to pick their battles wisely.
 
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Sometimes airplanes break. But the NTSB cant find any evidence of pre crash breaking. So they say its pilot error because it looks like a stall/spin/hit.
Usually, if they can't find a material cause they are pretty good about stating 'for undetermined reasons'. Now if the pilot enters a stall spin after the initial casualty, they will note that as pilot error.
 
Thanks for the input!

I always thought, (In the past) that they're at least 90% accurate. Does insurance companies pressure them to provide an accurate analysis?

How does insurance companies determine the cause of the accident? Surely they need an accurate analysis!

You may not be aware that federal law prohibits the use of NTSB reports in litigation.
 
I had a partial loss of power and an off-field landing that did a fair amount of damage. There was no in-person investigation, just the usual form 6120.1, a phone interview, and some photographs.

The report on mine was generally accurate, as far as what was included and what was concluded. The sequence of some events was different from that which I had given in both my written and verbal reports, but not in a way that would change anyone's understanding of the accident.

I could see the errors in sequencing the events being material in different circumstances, but perhaps if that were the case, the investigator would have put more effort into getting it right.

In my case, the two cylinder, two stroke spit out a spark plug, so it was running on one cylinder. I confirmed that I had lost one cylinder, versus something happening to both cylinders, by the temperature drop on that cylinder's gauges. The report had the temperature drop and recognition of power loss in the other order, which would only really make sense if the power loss were gradual. Nobody needs gauges to alert them to a sudden loss of most of their power. I would guess that the prop was way too big for the reduced output, and the engine was only able to spin it enough to keep it from adding drag, and maybe put out a tiny bit of thrust. I'm guessing that the perceptible difference between what I had and a stopped prop would primarily be the sound.

I chose a dirt road through a pasture to land, as I knew that there would be no power poles, signs, traffic,...etc. I also figured that large rocks and similar obstacles would have been cleared away. The problem was that the road was on an up-slope that I was not able to detect before I was committed. I had already done everything that I could to get as slow as possible without stalling, so there was no chance of following the terrain back up the slope.

I had chosen a stretch just past a gate, in order to get the longest possible straight stretch of runway (remember that I didn't perceive the slope yet when I made that decision). As a consequence, I couldn't trade my last few feet of altitude for speed and then flare up the slope a bit. All I could do was fly to the center of the wreckage. I did drop the nose slightly when I knew that I would clear the gate, but didn't get enough speed to make much of a flare, as we are talking about an 8-10' "dive", at most.

The landing was 3-point, with enough of a vertical component to tear the gear up and bend some 4130 tubes in the area around the gear, but with enough forward speed that there was still a fair amount of lift, and the impact wasn't too damaging to the soft and fragile pink thing inside.
 
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I know of an accident in which gross weight was in question. Pilot stated a specific amount of fuel which put the gross weight just below max useful load. The NTSB report stated almost full fuel which would have put the gross weight easily over max allowable weight.
Wouldn't have been to hard to either dip the tanks since they didn't puncture or drain them for an exact amount after the accident. Plane still was able to park in a normal standing position.
End of the day, no one was hurt and so the report was vague on numbers.
That's how accurate that report was.
 
After a friend was killed in a local crash and after the dust had settled I called the NTSB to ask about the crash investigation and their findings, which had been made public. The local NTSB chief was friendly and took the time to have a very interesting conversation with me. He earned my respect for what he said and for how he said it. They were thorough in my friend's accident investigation and went from the same list of assumptions any pilot would have regarding potential causes. Rule out equipment failures and all that's left is "the pilot's failure to maintain control". It sucks but they have to come up with something.
 
http://www.ntsb.gov/about/pages/default.aspx

I don't think the NTSB is interested in determining every detail of a GA accident. Their main objective is to gather enough data to create statistically significant reports and suggestions to further transportation safety.

An isolated incident, no matter how mysterious or intriguing, can ultimately be dismissed by the NTSB. The wings falling off of 6 planes of the same make within 6 months, however, will get a lot more attention and resources.

Once an accident can be assigned to a generalized superset class of accidents, they don't always have a need to figure out which nut or which gear caused the engine failure.
 
I think they often do a great job of finding a cause out of a pile of parts.

But you'll never really know what happened unless you were there. Take the following crash: Without video, it probably would have been the old "pilot's failure to maintain airspeed resulting in a stall." But with the video, they determined that a wind shift was the main cause.

https://www.youtube.com/watch?v=jjRPY4_XKy0

How did that video ( which I remember well) prove it was a wind shift?
 
How did that video ( which I remember well) prove it was a wind shift?

DA and overloading were also factors. Here is an AOPA story about it:

http://www.aopa.org/Pilot-Resources...rts/Film-crew-captures-density-altitude-crash

Accident investigators determined that the aircraft weighed approximately 4,095 pounds at takeoff—nearly 100 pounds over the Bonanza’s modified maximum gross weight. Examination of the accident video also revealed shifting wind patterns at the airport, which is surrounded by buildings and located in a slight geographical bowl. During the aircraft’s takeoff roll, the midfield windsock appears limp. At the departure end of the runway, however, foliage can be seen waving in a moderate breeze. According to calculations, the pilot likely encountered an abrupt 10-knot crosswind from the left, possibly with a tailwind component.

The NTSB concluded that the Bonanza’s sudden encounter with a wind shift during the initial takeoff climb resulted in degraded climb performance and a stall/mush condition. Factors contributing to the accident were the airplane’s overweight condition, the high density altitude, the pilot’s inability to compensate for the sudden wind shift, and rising terrain in the departure path.
 
Often, if the accident is not fatal, the NTSB investigator may never visit the accident site. Often the report is compiled from data gleaned from the FAA, the pilot, owner, the manufacturer, witnesses, police, etc. They are Congressionally mandated to determine probable cause and issue safety recommendations. Their findings how no bearing on enforcement action, and generally cannot be used as evidence in civil trials. As far as accuracy, I believe they are reasonably accurate considering the time and budget limitations associated with conducting an accident investigation. I tend to discount accusations of conspiracies, etc. Lots of folks have an agenda in the course of an investigation; generally the NTSB isn't one of them.
 
DA and overloading were also factors. Here is an AOPA story about it:

http://www.aopa.org/Pilot-Resources...rts/Film-crew-captures-density-altitude-crash
So.....in other words, if it hadn't been for the wind shift, the pilot would have gotten away with taking off from a high DA airport in an overloaded airplane.....

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So.....in other words, if it hadn't been for the wind shift, the pilot would have gotten away with taking off from a high DA airport in an overloaded airplane.....

Appears so. It was the final link in the accident chain.
 
Often/frequently, the listed probable cause is no more probable than another. Often enough, the listed cause is less likely than an alternative. For GA, unless there area bunch of bodies, or someone important dead, it's usually a cursory and subjective opinion.

For big iron, and/or politically important accidents, I think they can be very through, and amazingly insightful. But if you or I make a crater, they'll pick a cause from column A or column B, and get on with their day.

And really, for one or two fatalities in a light plane, who really cares, beyond their loved ones and some other GA pilots?
 
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