crashed

hharney · #1 02-23-10, 05:41 PM

Here is the prelim report for N12NA

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

WebMaster · #2 02-24-10, 05:27 AM

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.

WebMaster · #3 02-24-10, 06:22 AM

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.

Roger · #4 02-24-10, 06:39 AM

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

jack374dn · #5 02-24-10, 07:43 AM

Quote:

Originally Posted by Roger

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 + ...

hharney · #6 02-24-10, 02:14 PM

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

WebMaster · #7 02-24-10, 05:26 PM

Quote:

Originally Posted by jack374dn

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 + ...

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

#8 02-24-10, 10:23 PM

See attached diagram for wing station's.

edasmus · #9 02-24-10, 11:34 PM

"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