General > General Technical Chat

F35 jet has crashed into the sea...why?

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coppercone2:
how about a sea worthy roomba to clean the decks?

wasyoungonce:

--- Quote from: jc101 on November 19, 2021, 07:39:12 pm ---Rumour in the aviation world is FOD ingest on take-off leading to engine failure. 
Pilot ejected and landed back on the carrier deck. 

Did they not store enough brooms on the carrier when it left port?

--- End quote ---

FOD walks are routine done on Flightline (FL) every morning or before ops and if necessary during the day again.   Its somewhat common for ground support equipment like jammers (used to life bombs, fuel tanks) to loose nuts and bolts as they are not looked after as much as the Acft.   They are used constantly.

All those who work FL always look out for FOD, but it does happen things fall off, jeez I've seen a Flap fall off an F18(un-seen hinge fatigue cracks).   Plus the salt air environ is extremely corrosive.    I used to be amazed at the USN Acft patchwork paint as they cut back corrosion and re-painted areas.   The F35 in the Royal navy are the F35B so uses ducted fan for vertical take off....pretty difficult to FOD that but hey...never say never.

TimNJ:

--- Quote from: wasyoungonce on November 19, 2021, 07:22:01 am ---
--- Quote from: Faringdon on November 18, 2021, 05:55:17 pm ---Anybody know why this £100 million pound F35 jet went down?...

The Western world has outsourced most of its “general electronics” out to the Far East now..
--- End quote ---

Nothing electronic on the F35 is made in China.   I'm ex Avionics many decades from mirage IIIO/FA18/F111/Pavetack/FLIR (Australia) ....no, repeat no Chinese parts were ever used in the F18 or I believe the F35.  The US would not allow it as the parts have to be all Mil Spec with full mil Spec supply line reporting and accounting.  That itself is a whole can or worms with bogus or fake parts.   Being Military Acft parts are not cheap its easy to see why people will make bogus parts.  The have been reports years back of some bogus F18 undercarriage brackets...that were easily identifiable as bogus.

There was some crap back awhile about a PCB mfgr taken over that had made PCBs for F35 Acft.  But it was never stated any of these went into the F35 and the PCBs were blank.  Being that Acft Avionic PCBs are multilayer Mil Spec ....you can bet they are USA sourced.

Oh I did use Russian miniature power valves in the Mirage servo control (flight controls).   They worked well, better than the French Valves, lower noise.  Oh those Ruskies......!  Make good valves



--- Quote from: dietert1 on November 19, 2021, 06:47:19 am ---In the 1960s the german government bought from the US more than 900 "Starfighters" ....Regards, Dieter

--- End quote ---

Used to be called "widow maker" due to its instability in Roll and such high pwr, roll coupling.  The Mirage IIIO also had its issues, engine, Undercarriage and roll coupling (not as bad as F104).   The pwrs to be said they would never buy another single engine fighter.....apparently that lesson is lost in Australia.  I can count over a dozen times we save F18s from the mere fact it had 2 engines.   That said the old F404 was the beginning of the "hot high performance reliable" engines.

But this F35 crash...I think the Royal Airforce uses F35B so not sure it it was Duct fan fail on take off or it was short take off?  But it crashed soon after take off.

Oh my Chinese made Fluke and Rigol and PSUs work just nicely...along with my Chinese Uni-T meters

--- End quote ---

Don't military electronics use a ton of COTS (commercial off the shelf) components these days? Supposedly, the quality of COTS components is much better than 30 or 40 years ago. You can sort of prove this if you do an MTBF calculation for a given COTS assembly with both MIL-HBK-217 (1991) and Telcordia SR-332 (2011). You'll see the 1991 MIL-HBK number comes out way lower.

To me, it seems almost impossible to have a BOM with 100% Mil-spec parts these days. I have a hard time believing that even a deep-pocketed defense contractor can get TI, et. al. to make military grade versions of their normal stuff.

And to that end, I feel like there is a large percentage of (IC's in particular) that the main (only?) fab site is in China, so can you plain just not use those? Or maybe the Pentagon is just signing hella waivers.


David Hess:
The sea came up and hit it.

wasyoungonce:

--- Quote from: TimNJ on November 19, 2021, 11:29:04 pm ---
To me, it seems almost impossible to have a BOM with 100% Mil-spec parts these days. I have a hard time believing that even a deep-pocketed defense contractor can get TI, et. al. to make military grade versions of their normal stuff.

--- End quote ---

I thik many mfgrs parallel run production but test and bin their best parts for MilSpec then tun them thru tighter testing and assurances.  Mil Spec covers all specifications of the part from tolerances, temp ratings, radiation hardened, QA inspection, storage and test process even the manufacturing conditions...yada yada yada.   

I pulled up an old USA electronics parts 1987 MIL spec doc....for a gander...was stating that for Metallised Film capacitors must be +/-2% tolerance and this was measured at end of life.  I have no idea how they determine EOL, Jeez that's tight.

So yes, the only way you can guarantee this is to be a certified Mil Spec parts supplier meaning your parts will not be cheap this is why these Acft cost so much.  To think the buy price is just a portion, the ongoing life support costs are far higher.

This doesn't mean everything is perfect.  I've seen repaired F18 flap from external supplier repaired to Mil Spec.....we boroscope inspected thru its weep holes..could see de-bonded rivets  not clinching alloy doubles and carbonfibre.   The crap that some suppliers tried to get away with defies belief.  F18 flir LASER assy straight from factory.....qty 10, 2 were rattling inside...loose or extra screws...total fail.

So much for standards.

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