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NTSB releases preliminary report on deadly B-17 crash

WINDSOR LOCKS, CT (WFSB) - A preliminary report on a deadly vintage plane crash in Windsor Locks was released by transportation officials on Tuesday morning. The B-17 bomber slammed into a deicing facility at Bradley International Airport on Oct. 2. ( More...

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Parker Merrill 14
The several posts suggesting the anti-knock rating of 100LL Avgas causing engine malfunction in this crash are not based on available information. N93012 was a Boeing model B17-G manufactured in 1944 with four Wright R-1820-97 1,200-horsepower engines (NTSB Preliminary Report). This engine model corresponds with Boeing’s documentation which specifies “not less than 100 octane gasoline” (Boeing B17-G Field Service Manual, Jan 1945, pp 66 and 453). ExxonMobil states “Aviation Gasoline 100LL has been approved by the major aircraft engine manufacturers for use in aircraft engines originally designed for operation on the following grades: 80/87, 100/130 and the discontinued 91/98.” (ExxonMobil Avgas, June 2018). Shell states “Avgas 100 and/or Avgas 100LL can be used in aircraft spark-ignition piston engines, for which the engine manufacturer has approved this grade of fuel. Although having the same performance in terms of anti-knock ratings, the two grades are distinguishable by tetra-ethyl lead (TEL) content and color...” (Shell Fuels Technical Data Sheet, Oct 2007).

While some other fuel issue could be a factor, the anti-knock rating of 100LL most likely isn’t. Conjecture about “115/145 octane Avgas”, “Using 100LL instead of the fuel these engines were designed to run on”, or “Low Octane could make the Mags look faulty where they were not” are not supported in this incident.

Yes, definitely we should wait for the final NTSB report.
GraemeSmith 2
^^^^This by Parker Merrill^^^^^

Those Wright Cyclones were originally designed in the 1930's to run on 80 Octane and were upped to 100 by the end of WWII.


If there is one thing that the NTSB prelim has settled it is the persistent "reliable off the record" rumor going around here in New England that it was a Jet-A misfuel.
Ken Hardy 1
There was an incident many years ago here in Atlanta where a Martin 440 had Jet-A put in during a refueling stop at Epps Air at PDK airport, the aircraft took off but only made it about 10 miles before it crash landed in the medium of I-285 expressway
bbabis 1
Good information Parker. One can never have too much, at least when it comes to aviation. And we most definitely look forward to the NTSB report so as to better understand and learn from this tragedy. In the mean time, we make observations and speculate on possibilities. For good or bad, I guarantee you that the NTSB pays attention to these squawks. A couple of years ago, due to a post I made on FA about a particular accident, the NTSB official in charge of that accident called me for more information. After the pleasant call, I asked how he got my phone number. He said "they're the government." Enough said.
harold smith 5
I’m sure the takeoff weight was very low, compared to a maximum weight takeoff in world war 2.
Even with 100LL gas and 2 engines shut down, he should have been able to land safely.
I flew DC3s for many years. 14 engine failures, 3 on takeoff and 1 that wouldn’t feather. I was at max weight, and was able to land safely. Maybe something else going on.
14!? When did it go from terrifying to complacency? Obviously, you had a great deal of faith in the plane. Was that normal?
Steven Thomas 1
During my fourth engine failure my verbal reaction was "well that sucks," then I glided to the runway (I was already on downwind). I wasn't worked up or full of adrenaline like I was with previous ones. I was more annoyed than anything.
Ken Hardy 4
Its doubtful that the fuel octane was the cause of failure, the original engines were set to run on 115/145 but that fuel has not been around for many years and I am sure the engines had been timed to run on 100 LL because that's what you find at the majority of airports where this aircraft had been used to going. The NTSB will get to the bottom of the problem
Dubslow 3
where's the prelim on the B767 crash
siriusloon 2
Either not released yet or you're not looking in the right place if it has been released.
The preliminary report really tells nothing that is not already known about this incident.
Coalora 4
That's an NTSB prelim report for you. They generally detail the events of the incident. The full investigatory report on probable cause is what comes much later.
That's not entirely true, we had no report of the low octane fuel used, which could very easily degrade the engines to a point of not producing adequate power with one engine down. So, we will wait for the final report to the cause of the crash.
Low octane fuel? Did I miss that somewhere? I thought the report specifically called out that they verified 100LL was put into the aircraft.
Read further down
It's a relatively low octane fuel so now the question becomes is low octane fuel strong enough to power this aircraft with just three engine. Back in WWII they used super charged fuels. Higher octane. Much stronger and they were powerful," Teiger said.
Bryan Nethery 2
You're quoting something from the news report, not the NTSB preliminary report. The NTSB does not refer to the fuel as "low octane".
sparkie624 1
That is true, but the NTSB did say it in different working... News media just making more understandable for the person who would not know the difference...

"On the morning of the accident flight, an airport lineman at BDL assisted the loadmaster as he
added 160 gallons of 100LL aviation fuel to the accident airplane. The lineman stated that the
accident airplane was the first to be fueled with 100LL fuel that day."

From the "National Transportation Safety Board Aviation Accident Preliminary Report" attached to the article.
rmchambers 1
Higher octane doesn't imply more power it implies more resistance to pre-ignition or detonation.

Putting high octane gas in your car won't make it go any faster if it's not a high compression engine.

I'm not quite sure what the doctor was talking about.
JedFR 1
IIRC, the octane rating doesn't have anything to do with the "power" of the fuel, just the knock rating. That's at least true in auto fuel 87 vs. 93.
Jim Newton 1
Correct. 100LL is the fuel they have been using for these aircraft. The fuel truck was also quarantined and no anomaly’s were found in the fuel.
Can anyone comment on the flaps being in a retracted position? I would think the flaps would normally be extended to approach flaps. Perhaps without the flaps extended it caused a loss of lift at low speed and resulted in the impact 1000 feet prior to the runway. Of course this is speculation and we need to wait for the final report... But it stood out to me when I read that.
bbabis 2
What I get from the information so far is that the plane was struggling to get to the runway and it touched down well short but did not stall. Any flaps/drag would have caused the plane to come up even shorter. The crew was really trying to save that ship but it just wasn't to be.
David Tripp 1
I was confused by that. It looks like in the photo that they were extended.
sparkie624 1
I wonder if they have had time to tear down the engine to see if there is anything obvious in the one that failed!
a mentor 1
Why can't we accept the pilot's comment: Rough Mag on #4? All this conjecture is BS
bbabis 1
You generally don't shutdown and feather an engine with a rough mag when you need all the power you can get.
We know that at least #4 was feathered and #3 showed signs of being near feathered as per the prelim. They also came up well short of the runway as if #3 died somewhere before landing.
sparkie624 1
Very True.. Think that it must be more than that.... Low Octane could make the Mags look faulty where they were not.
I notice #4 (the suspect engine) had over 800hrs SMOH at the time of the accident, the other three engines were overhauled at annual and were low time. I wonder what the TBO was used on these engines in service. Most military applications I would imagine would carry much lower TBO, possibly even only a few hundred hours. That doesn’t explain the attempted feather and failure on 3 but it may help explain why #4 died.
crk112 1
Direct link to NTSB report straight from the source
I spoke to crew at an event a number of years ago at an event at Republic Airport. I do not remember if the airplane inferred to was a B-17 or a B-29, but I was told that newer versions of the engine or a different one were required to be installed. I am wondering if those engines were the newer ones.
jmonroe 1
In any multi-engine aircraft, speed is the critical issue. He may have never reached blueline where the airplane will at least maintain altitude. He probably had his 2 left engines at max power and the 2 right engines either totally or partially shut down. He seems to have been in a constant right turn since he started losing engines. Flaps would have helped him hit the ground at a slower speed but he would have hit the ground sooner given his reduced power. He must have flown right over the terminal building. Read (or watch the movie) Fate is the Hunter by Ernest Gann.
Jim Newton 1
I thought the fuel nozzles for Jet/A were changed after Bob Hoover’s crash.
bbabis 0
The note on the fuel used is very crucial. Using 100LL instead of the fuel these engines were designed to run on, which is no longer available, basically makes every takeoff a three engine takeoff power wise. The loss of an engine then becomes very critical. It is not known, but if the crew pushed #3 engine up in an attempt to help with the loss of #4, that engine may also have deteriorated from the low octane fuel. It's clear that they struggled around the pattern. As Sparkie mentioned, the engine tear downs will help tell the story.
bbabis 0
I found that Purple 115/145 octane Avgas is still available in very limited quantities for special events such as air racing where maximum HP from the engines is needed. It has lots of lead and I'm sure that it is also very expensive. The 1200hp per engine that the B-17 specs speak of is with this fuel. Maybe someone more knowledgable on octane can tell us what that engine might develop with 100LL.
By the early 1970s the avgas market had become so small that the major oil companies were finding it uneconomical to produce and market two separate avgas products. Their logic was that they had to produce a product that met the 100/130 spec, so why not just eliminate the lower volume 80/87 product? The only negative to using 100/130 in an 80/87 engine was the higher lead content. The solution was to offer a 100/130 grade of fuel with a limit on the amount of lead in the fuel. The oil companies found that they could still meet the 100/130 octane specification with only 2 grams of lead per gallon if they increased the severity of the refinery process and topped off the blend with toluene concentrate.


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