a. Low time Right-seater flying and a quite experienced captain in the LHS being so distracted by the unstable approach that he doesn't lower any flap (normally a RH seater's duty). They may have also landed with a slight tailwind component (judging from the post-crash smoke, there's little wind at all however).
GA SOP for ILS approach is A/P on until glideslope intercept unless NOTAM reveals reported significant deficiencies in an ILS transmitter or the aircraft's receiver.
b. RH seater trying so hard to plant it at high-speed (due to the total lack of flap) that he drives the nosewheel in - in a classic porpoise cycle initiation (i.e. a nose-to-main-gear continuing reverberation). (which explains some of the pax descriptions of what they felt).
Ever flown behind a GA 737 on approach? Bloody slow! The cowboys have moved to other airlines for faster promotional schemes and faster money!
It would seem to be naught but a classically incompetent very heavy landing carried out by a tyro and supervised very maladroitly by a non-instructor type - notwithstanding any claims of wind-shear.
Perhaps you'd like me to give you the phone numbers of Capt. Marwoto, or F/O Gagam, or perhaps a coffee session with Marwoto's seniors in Garuda? Perhaps that would change your view... or perhaps not...
If we're sticking to what we have evidence for...
The cockpit wasn't attached to the rest of the fuse when it all came to rest and Captain Marwoto quickly shinnied out the flightdeck hatch.
Please have a look at the video... before fire took over, cockpit WAS still attached.
If you look at:
http://www2.indoflyer.net/botak/montage1.jpg you can see the elevators were slightly up also, which could mean cables still connected prior to fire.
It's clear in the composite image that the flaps are still up.
I disagree flaps are up.
http://www2.indoflyer.net/botak/montage2.jpg shows flaps on the left wing deployed but not at 30 as per GA's standard operating procedures. The wing on top is the right wing, slats deployed.
And in
http://www2.indoflyer.net/botak/montage1.jpg you can see the inboard leading edge flaps on the left wing were deployed (not just hanging).
Now whether the flap position on the photos are the same as on the approach, we'd have to wait and see, but yes, IT WAS DEPLOYED! If trained eyewitnesses can identify the spoiler being deployed, I'm sure they'd be able to tell if flaps were retracted, somewhere near flap15, or somewhere near flap30/40 as it went by them!
I myself only noticed the flap position on the montage not more than 24hrs ago, and it CAN match a botched flap 15 approach. Whether that was what happened or not, for the moment we can only guess, but please, silly guesses aren't useful.
The head of Garuda's pilot association managed to interview Capt. Marwoto last night, and he quoted that there was a "minor problem" with the aircraft "which was solved and acted upon prior to the landing." Now whether Capt. Marwoto's having selective amnesia or not in his interview, we'd have to wait and see.
Now if the FDRs reveal the opposite of you say Dagger Dirk, I wonder if you'd claim the whole investigation's a cover up?
If you want to speculate, speculate responsibly! Why? As Clandestino said, learning from mishaps is one way to improve... slapping comments like "tyro non-instructor type", or "low hour newbie" isn't one of those ways, unless you know directly or indirectly through someone.
Furthermore, the purser died on duty, reportedly amidst evacuating the business class section, where there were some deaths... I hope you don't brand him as trying to sneak out of the aircraft quickly!
PK-KAR