crashed
 

one down this afternoon near Trenton n.j. maybe 5 dead

http://www.nj.com/news/index.ssf/201..._on_landi.html

This aircraft has Winglets, as depicted in the video on the link above. I have to speculate that this may be N12NA, a Riley Super Skyrocket. Again, this is only a guess based on the winglets and the paint scheme. This aircraft, N12NA, has the extended wing tip tanks also as shown in the picture below. Tragic accident, the media makes it sound like something came off the aircraft while it was landing. This is awful.

http://www.nj.com/news/index.ssf/201...lane_cras.html


By looking at this photo I can see the boom with N12 on it.

If you watch the video you'll see the right wing tip broken off over the runway. I noticed it had the wing tip mods too. Not sure if the two things are related, but here we are all talking about the wing root inspections.....perhaps Cessna overlooked something. Notice how the wing/fuselage mounts are still connected even after the accident.

Terrible . Hard to surmise what happened at this point, because of all the different info from witnesses. Some say the plane was going very fast which doesn't sound right for a take off. But the gear was allegedly up, so it would appear that it could have rotated and cycled up. More likely a landing or low approach, or missed. For the wing tip to be in the position it is in, it seems like it might have hit before the accident, i.e. scrapped the runway, broke off, then flipped? Marks on the runway may tell the story. Regadless, what a horrible thing.

P337
 

WALL TOWNSHIP -- A small plane broke apart over Monmouth Executive Airport in Wall Township today, sending the aircraft into a nose dive that destroyed the plane and killed at least two people. Three others remain missing as authorities continue to search the debris field, officials said.

Eric Ross, a helicopter pilot, witnessed the plane crash at Monmouth Executive Airport. Eric Ross, 47, was flying near the airport at the time of the crash and reported it was a Cessna 337 Skymaster, a twin-engine plane with propellers on the front and rear of the fuselage. Ross said the plane appeared to be making a "high-speed, low pass across the runway" just before the crash. Ross said he saw "mangled bodies" inside the plane

Reports are saying now that they have located two of the missing and that they were ejected from the aircraft. A fifth person is still missing. Three of the five were related, two of the five were younger, one teen and one child. There may have been family watching them leave from the ground but may not have seen the crash. They were going to NYC for a sightseeing flight.

It appears that it probably was N12NA. The Fox NY web site's TV reporter broadcast says that: all five victims have been recovered, that the FAA said it was a 1973 T337 registered to Jack Air LLC, Wilmington, Delaware (which matches N12NA's FAA Registration info), and that an eyewitness saw the aircraft with the gear retracted approach the runway, hit the runway with the gear retracted, and pull up after hitting the runway.

I keep wondering if they were just doing a low approach fly-by, like many of us do. If that was the intent, what went wrong? The right wing tip was not damaged from hitting the runway but appears to have just broke off at the extended fuel cell attach point. If the fuel cell broke off while performing a fly-by at high speed this could roll the aircraft clockwise very quickly. One would expect that it may look similar to the reports that witness's described. If this is the case why did the fuel cell separate? High speed? Structural? We may never know.


Interesting story relating to the crash:

http://www.examiner.com/x-35334-Newa...illfated-plane

Did this aircraft have the extended wing mod. to increase gross take-off weight ?

Jack

I don't know which optional tanks it had. Given the winglets are Aviation Enterprises maybe the fuel cells are also. I know that some of the optional tip tanks do have a jetison system so that if you have to land before exhausting the fuel the fuel can be dumped so that the gross weight is legal for landing. The increased gross weight is for T/O and flight only and not landing.

Here is the info on the Flint extended tip tanks. It increases the Gross Wgt to 4,630 except where the GW is already 4,700 from Cessna. No dump system on the Flint Kit.

http://www.flintaero.com/337.htm

Thanks Herb ....

Jack

Has there been a report released on the may 2008 skymaster that went down in Millville, Cumberland County, with Stephen Claussen on board?
________
RED HEAD GIRL LIVE

Millville/Eagle Nest Accident
 

If I remember reading this incident it had something to do with fuel management. Here is the dialog findings about the fuel system.

The main tanks contained either trace amounts, or were completely devoid, of fuel. The right auxiliary tank contained approximately 11 gallons, and the left auxiliary tank contained approximately 2 gallons. The recovered fuel was clear and bright, with no visible contaminants. Tests with water-detection paste were negative, which indicated that no water was present in the fuel.

The fuel selector valve handle for the front engine was found in the "Left Aux" position, and the corresponding fuel selector valve was found set to the port from the left auxiliary tank. The fuel selector valve handle for the rear engine was found in the "Right Main" position, and the corresponding fuel selector valve was found set to an unused port, which was the "off" position.


Here's the full report

http://www.ntsb.gov/ntsb/brief2.asp?...08FA184&akey=1

Weight and Balance Report
http://www.ntsb.gov/Dockets/Aviation...184/424353.pdf

Wow, a fuel thing. Seems to be the cause of many 337 accidents. My rules: 1. Always top off the mains 2. Never fly more than 3 hours on the mains 3. Never switch the aux tanks at the same time, wait at least 5-10 minutes 4. Always feel for the indent 5. Grease the fuel valves during each annual 6. Burn main tanks for at least 2 hours before switching to the aux tanks (book says 1 hour, but why do just the minimum?)

Comments?

I like to use my aux tanks as soon as possible on long trips because you can't use the aux for landing. I wait the 60 minutes on the mains and then switch to the aux's and finish them early into the trip. I let the aux's run for 60 minutes and then switch the front back to the main while the rear runs out on the aux then once the main is back in place on the rear I switch the front back to the aux and run it out. Typically about 75 - 80 minutes per aux at normal cruise.

Thanks for the information. This came up cross referencing the reports on N12NA. I did not recall the history on that accident so thanks for the details. It's a valuable reminder on fuel management!
________
Ipad Cases

NTSB Report Posted
 

Here is the prelim report for N12NA

http://www.ntsb.gov/ntsb/brief.asp?e...15X82210&key=1

Sad incident, but I find it interesting that even with the wing separating from the aircraft, the failure was out board of the strut, and the wing to fuselage integrity was not compromised.


It would seem to eliminate the need to remove the wings for Cessna's SIDs.

Lets do a little Math
 

Reading the preliminary report, a couple of things struck me.
Radar showed it doing 171 KTS at 600 MSL, 188 degrees from the reported wind.
KBLM is at 153 ft, MSL. So, he was 447 feet AGL.
Presumably, he was descending, and building speed when radar track was lost, because reports are that he was about 50 AGL, or 203 MSL.

At 171, with 7 kts of head wind, he was doing, and I know this is simplified, but he was doing 204 MPH IAS. I remember when Herb put his winglets on, that he had to remark the air speed indicator, because the winglets had a VNE of 201 MPH. So, before he got down on the deck and going really fast, he was already exceeding the VNE for the airframe.

NY preliminary NTSB
 

So far this appears to be the classic example of why you never want to be in an airplane where the last thing heard by the pilot was "watch this".

He had apparently accelerated through 171 knots in his dive by the time he was down at 600' from his 1400' starting point going in the opposite direction. It would seem logical that if this dive run continued he would have been well over red line by the time he tried to pull up, and no one will ever know how quickly he (whoever was flying) tried to pull up. I could picture a 2000'+ fpm dive followed by an emergency yank back on the yoke once whoever was flying (or whoever took over) realized he may strike the runway. If that quick pull was done outside of the operating parameters of the aircraft "G" envelope, than this could be pure pilot error.

And/or, does anybody know if the wing tip tank STC requires drilling through the internal wing structure, and if so, where does that drilling take place in relation to this break?

http://www.337skymaster.com/messages...uote=1&p=15274

According to the NTSB the wing seperated at Sta. 177 .. Out of interest, I am going to establish Sta. 177 on 74DN this morning ... I have install data on ?? tip tank installation unless it has been disgarded ... Will let all know my findings ...

74DN super skyrocket ... From first hand experience with the acceleration potential of my airplane @ less that 1000 fpm dive @ 2300 / 32" M.P... Roger's comment is my opinion is right on ... RED LINE + ...

Media Report On The Ntsb Release
 

I don't know if it is practical for you to do so, but could you place a marker of some sort on the wing, coinciding with Station 177, and then take a picture.
It would help all of us to visualize where that is, in relation to the strut and it's attach point.

Thanks,
Larry

See attached diagram for wing station's.

"The last contact was at 15:47:00, the airplane was at 600 ft msl, on a heading of 062 degrees at a ground speed of 171 knots."

"The surface weather observation at BLM at 1535 was winds 250 degrees at 7 knots; visibility 10 statute miles; sky condition clear; temperature 03 degrees Celsius; altimeter 29.76 inches of mercury."

These statements are quoted from the preliminary report. This would support a conclusion of an indicated airspeed of less than 171 knots at this point. The aircraft most likely had a tail wind component at this point making the ground speed higher than the indicated airspeed. The winds, though light, appear to be from the WSW and the aircraft was heading ENE at last radar contact.

I, like the rest of you, had the same thought about a possible overspeed and abrupt pull up. Maybe that happened and maybe it did not. At the last radar data, he probably was not at an overspeed.

Does this make sense or do I have it backwards?

Ed

The math would be as follows: He decended from 1400msl to 600 msl in a left bank and accelerated 23 kts from the beginning top of his decending dive as noted on radar. It started at 148deg - at 156kts, and the next and last return was 62 deg at 171kts . If he maintained the same descent profile then it is: 23 x 450 / 800 = 13kts in additional airspeed at 150msl/ground = 184Kts +/-

My book says: Va 137KIAS at max gross: Do not make full or abrupt control movements above this speed. Further is says: Vno 168 KIAS : Do not exceed this speed except in smooth air, and then only with caution.

So unless this skymaster had an emergency chute that slowed it down in the last 450' of it's dive, than this was clearly a case of flying the aircraft way outside the parameters of Va, or even Vno

Even if the aircraft exceeded 171 knots, the normal engineering factor is 150% (also known as the "ultimate load limit"). So, the structure should have been able to hold together until at least Vne x 1.5 (for example 171knots x 1.5 = 256.5knots). If your aircraft tears apart right at Vne, then imagine how much damage you would be doing flying one knot below Vne. That's why there's normal an engineering factor of 150%.

However, if the structure was damaged it might not make it to 150% over, such as corrosion. I've found lots of corrosion in the wing tips before. It's possible. However, from my many accident investigations experience...it's usually a "change" that caused it. My Vegas odds are on improper wing tip modifications & or design. That's were I would start as an investigator.

Comments?

Your comment sounds logical to me. I am certainly no engineer but it seems to me that flight control movement is very important as well. Meaning one could be operating at speeds well below Vne and even at Va and still damage the aircraft with abrupt control movements. My memory is a little fuzzy but I thought that the Airbus that shed it's vertical tail in New York shortly after 9/11 was at about 250KIAS when that occurred. I do not claim to know what the appropriate speeds are for passenger jet aircraft to maneuver around are but I believe by most standards 250 knots is relatively slow for that type.

I just want to add that though I think it is good to discuss this unfortunate accident we should all be patient and let the final report be published before rushing to any conclusions. I know we all want to believe our airplanes are safe and they most likely are but nonetheless a structural failure occurred and I certainly want to know why. It will take time to get these results.

Ed

I don't believe the "findings" of that Airbus accident....or TWA flight 800 either. But you are right, maneuvering can cause damage....especially at high speed. Assuming 137kts is the Va speed, then 137 x 1.5 = 205.5kts. That's faster than the 171 kts we're talking about, but with age/damage/corrosion, etc. the structure might not make it all the way to 150%. So, we'll see. But as an investigator I'd start with the wing mods.

A 4500lb car travelling at 180 mph experiences a 20G force if stopped in 50'. Now granted the accident aircraft did not "initially" stop in 50', but instead apparently changed his vetor angle at the bottom of the dive. An angled stop is less severe than a 90' stop as well. That being said if instead of "stopping" his dive he over pulled, then his vector angle change was more severe than a "stop", albeit beginning at an angle.

In the heat of fear, if he pulled this plane up at the last minute, especially given the large elevator on the 337 which will do a damn good job stopping or deflecting the descent, I can see the plane stopping it's descent in a distance that would cause some serious G's loading of the wings. Meanwhile if there were alterations to the tips and added weight of fuel in the tips, this is a no-brainer.

"Watch this"

It is possible, in that last instant before wanting to hit the runway he could have pull back hard and created a peak load over the 150% structural limit on the wing. Extending the wing with the tip tanks could also increase the moment arm the load has to work on. It sounds like he was fully loaded with people and fuel and near max gross weight. There is also the possibility that he has done this maneuver many times before and over stressed the wing, creating fracture or deformation. This might have been the straw that broke the camel’s back.

I think at wing station 177 is where the autopilot bridle cables go through the wing spar

It's important to remember that the posted G limits are symmetrical. If he was rolling and pulling, inducing assymetrical G's, the aircraft's G tolerance is greatly reduced. While we won't know until the NTSB finishes the investigation, it appears much more likely that it's pilot error, he pulled a wing off, versus an aircraft mechanical failure.
The aircraft I flew until recently had Flint tip tanks. They are required to have (approximately) 12 gallons unitl the aircraft's gross weight was reduced (I don't remember the numbers). My technique was to fill the tips, put in the fuel required for the leg in the mains. I would burn the mains until they were about to go below 20 gallons per side, then transfer the tips to land with about 20 gallons per side, well in excess of the 45 minutes required.

Pressurized G model POH states:

The airplane is certified in the normal category. The normal category is applicable to airplanes intended for non-aerobatic operations. These include any maneuvers incidental to normal flight, stalls (except whip stalls) and turns in which the angle of bank is not more than 60 degrees. In connection with the foregoing, the following maximum certificated gross weight and flight load factors apply:

Gross Weight:
T/O Wgt ........................................4700 lbs.
Landing ........................................4465 lbs.

Flight Load Factor:
*Flaps up ......................................+3.8 -1.52
*Flaps down ..................................+2.0
*The design load factors are 150% if the above, and in all cases, the structure meets or exceeds design loads

Maneuvering Speed .......................155 MPH
*The maximum speed at which you may use abrupt control travel.

Never Exceed ................................230 MPH
Maximum Structural Cruising Speed .190 MPH

Most modifications will not adjust the operating limitations. Way too much expense involved. Although the extended fuel cells increase gross weight (normally not for landing but take off and cruise) the operating limitations remain as published by Cessna.

By speculation of the events, one would conclude that the pilot exceeded the operating limitations but don't rule out that there was some kind of damage or deterioration that was already present and the timing was not on their side.

Understood. But, 3.8 is symmetric G's; there isn't a published unsymmetric (rolling) G limit. All that is known is that it is less than the symmetric G tolerance, the aircraft is not stressed for to withstand 3.8G's in a rolling pull.
If he was at red line and pulled up abruptly, he clearly exceeded the airframe limits. If he did a rolling pull, he exceeded them to some unknown additional extent.
It will be interesting to see the investigation results. He could have easily pulled the wing off a aero time airframe....

In fact isn't the whole idea behind a screaming dive down to the runway with a last minute pull up, done in a manner to exert G-forces on the passengers? It's like a roller coaster ride.


"watch this"

Just for a visual, here is the location of Station 177. It is 46 inches from the end of the wing not counting the wingtip.

Thank You
 

It is way out on the wing, and the strut held. This should be an argument against the SID, at least the strut inspection.

I was discussing this today with a friend who is a chief metallurgist for P&W, and he mentioned something that puts this into perspective, ie. apparently the bobsleds running at the olympics are pulling 5.2G's going 90mph in a lateral turn.

Think about that for a moment, and then consider that for this crash the guy was doing over twice that speed and his G inducing pull was vertical ! I don't know the math on this, because we can't calculate the "unknown pull-up" but I can certainly see how easy it would be to snap a piece of wing off given what we believe occured.

Anybody want to bet a $100- burger that the word corrosion never comes up in the final report?

"watch this"

First and foremost...like everyone here.... I mean absolutely disrespect to the lost lives. I did not know them and I can only assume that they were very similar to me...love flying...enjoying life...everything was fun...until someone got hurt. S--- Happens. My gripe comes from the uninformed pundants blaming the airplane. The machine did its job.

This is all cessna needed to tighten the noose on their supplimental inspection extortion.

Naturally there is no mention in the media (even the aviation media) of the fact that the accident aircraft had an OUTBOARD wing failure.....no-where near the wing-root that is the subject of the inspection.

There is no mention in the articles that the left seat was a visiting pilot from Poland, the right seat (PIC) was a 2200hr ATP.

The three pax were the children of the left-seater

There were three other family members on the ground watching the take-off

The plane was modified to larger 300hp engines and 3-blade props ( hinting that the owner liked "performance"...certainly not a crime or even remotely a "bad thing" but its an important piece of the puzzle)

The plane was modified with extended tip-tanks (exactly like mine) which when empty reduces max maneuvering speed to 143kts ... at altitude...interpret that as reduced air density = reduced drag. Ergo, at lower altitudes or colder atmospheric conditions...greater desity....more resistance....even lower Max Maneuvering Speed)

The plane took off (90kts), retracted gear) climbed to pattern alt ( 100kts) turned downwind (125kts @ 900' msl) turned base (140kts) decended on final, flaps up, gear up, (155kts) leveled off 50' agl (165kts) nosed up sharply at the far end if the runway (171kts)

At which time the right wing tip snapped off and the plane rolled into the ground....but stayed significantly intact

I'm no accident investigator, but I interpret all that as a pilot doing an impromptu airshow for visiting friends...no problem...until you exceed the placarded performance limitations of your tip-extensions. Then s--- happens and you go from pilot to farmer in about...3 seconds.

But since the words "skymaster" and "wing" are used in the same article, it's a foregone conclusion that the 337 fleet should just go ahead and start lubing-up in preperation for cessena's regulatory boon-doggle.

The articles also don't mention that in the 2000+ production aircraft in 40+ years of military and civilian flights (including the rollercoaster rides of being an FAC "hedge runner").....not one has had the failure that the new inspection is supposed to address.

Oh well....I'm justglad that the supplimental inspection is SUPPOSED to be for commercial operators ..... For now.... But we are all waiting for the other shoe to drop.

I know I preaching to the choir and I'm still a new comer around here.

But it just infuriates me to have the media implying it was the airplanes fault.

I absolutely LOVE my skymaster. I did years of research that lead me to it. I've read and summarized every single 337 accident on file with the NTSB and I've made cross comparison charts with other types. The SkyMaster isnt perfect, but it is a DARN good plane if it is used properly...and is very forgiving if it is used improperly. But everything has its limits.

And it irritates the crap out of me that an unfortunate event resulted in the death of 5....tragedy for their families and friend....and will almost certainly have profound, possibly devistating results on the rest of us, too.

Again, no disrespect for the dead or their families. But, again, assuming he was anything like me, he would be the first to say "I was having fun and didnt pay attention to my airspeed...and it caught up with me. It wasn't the plane's fault...it was the PILOT IN COMMAND."

Just my rookie opinion, and probably not a very popular opinion.

Cole Reed