What can cause it to descend at such high rate?

What can cause it to descend at such high rate?

 

It could be a fully developed stall after pitching too high on a second go-around under manual control. It's happened before. Pilot fatigue and severe weather as possible contributing factors. The flight data recorder will have the answers eventually. 

Reports on news media emanating that they hit hurricane-speed winds in the area.

New  footage  just  appeared  and  now  showed  the aircraft  on fire  before  it  hit  the ground

When I discovered that they were in a holding pattern for 2 hours and the weather was bad, my first question was: why didn't they divert to the alternate airport???  If that one also had issues, then it's clear that they had enough fuel to get to multiple other airports within a couple hundred miles.

 

It's easy to play armchair pilot, but some pilot decisions are just hard to understand.

 

Dave

 

 

New  footage  just  appeared  and  now  showed  the aircraft  on fire  before  it  hit  the ground

Wrong, there is no such footage. The most common footage shows a 'light' striking ground but it is impossible to tell whether it is a ball of fire or simply aircraft lights. But there is another footage that clearly shows there was no fire, you can see all 3 aircraft lights and no trace of fire - hitting the ground, it is the first video at the top:

 

http://lifenews.ru/news/191340

Wrong, there is no such footage

 

 

http://www.9news.com.au/world/2016/03/19/23/38/flydubai-downplays-possibility-terrorism-caused-crash

When I discovered that they were in a holding pattern for 2 hours and the weather was bad, my first question was: why didn't they divert to the alternate airport???  If that one also had issues, then it's clear that they had enough fuel to get to multiple other airports within a couple hundred miles.

 

It's easy to play armchair pilot, but some pilot decisions are just hard to understand.

 

Dave

 

They were not in a hold for 2 hours, but rather 1 hour.

 

This is what is known so far:

http://aerotime.aero/en/civil/10967-flydubai-crash-in-russia-the-facts?utm_source=newsletter&utm_medium=email&utm_campaign=latest_facts_on_flydubais_tragic_accident_in_russia_aerotime

 

 

 

A scheduled flight from Dubai to Rostov-On-Don departed from Dubai International Airport at 22:20 local time (18:20 UTC) on 18 March 2016. The aircraft was scheduled to reach the destination point at 1:20 local time (UTC+3) on 19 March 2016. At 1:38 the aircraft commenced final approach to Rostov-On-Don airport, but 4 minutes later the pilots aborted the first approach at approx. 525 m (1725 ft). At 2:27 flydubai's Boeing 737-800 entered holding pattern at 4572 m (15 000 ft) to the southeast of the airport and leaves the pattern for a second approach at 3:28. Twelves minutes later, at 3:40 the pilots aborted the second approach at 472 m (1550 ft) and 5.6 km short of the runway. At 03:41 the aircraft disappeared from the radars and impacted terrain after a steep descent from 1211 m (3975 ft). The airplane completely disintegrated 253 m (830 ft) left of the runway, killing all 62 people on board.

When I discovered that they were in a holding pattern for 2 hours and the weather was bad, my first question was: why didn't they divert to the alternate airport???  If that one also had issues, then it's clear that they had enough fuel to get to multiple other airports within a couple hundred miles.

 

There were comments on the pprune forum mentioning that FlyDubai is an "out and back" airline, without the logistical support at nearby airports for dealing with passengers, transportation etc. A diversion would be a major headache, and with company culture being what it is, might have cost the crew their jobs. Major pressure to "get it done" regardless of local conditions, in other words.

 

Note that this is all speculation, but that's what you get in the early stages of an accident like this.

Maybe it is wise to wait for the investigation to shed light on what happened. The "black boxes" have been found, so provided they can be deciphered, the investigators should easily work out what happened.

http://www.9news.com.au/world/2016/03/19/23/38/flydubai-downplays-possibility-terrorism-caused-crash

This is your own interpretation that there is a fire. I don't see any ball of fire, footage is of too poor quality and aircraft lights can be mistaken for ball of fire. There is another footage of much higher quality and there is no fire here. Also as far as I know there is no single credible witness statement that would say anything about aircraft being on fir before hitting ground.

 

https://www.youtube.com/watch?v=KfuAJVAP0ZI

This is your own interpretation that there is a fire. I don't see any ball of fire, footage is of too poor quality and aircraft lights can be mistaken for ball of fire. There is another footage of much higher quality and there is no fire here. Also as far as I know there is no single credible witness statement that would say anything about aircraft being on fir before hitting ground.

 

https://www.youtube.com/watch?v=KfuAJVAP0ZI

 

+1

 

If I had to venture, and just *guess*, what happened, I'd say it was windshear during the 2nd go-around:

 

https://www.youtube.com/watch?v=CRUVDZjBAAs

 

In any case, let's the investigators do their job and not jump to any conclusions.

 

 

let's the investigators do their job and not jump to any conclusions.

++++1

Interim report has been issued by Russian IAC:

http://mak-iac.org/upload/iblock/19b/Interim%20Report%20A6-FDN%20(en).pdf

 

The aircraft attmpted two approaches and executed go-arounds on each

 

Significant findings on the second attempt:

 

 

In the course of the go-around the crew set flaps to 15° and retracted the landing gear.  At the height of 1900 ft (approx. 600 m) after reaching the pitch angle of 18° the pilot flying pushed on the control column, which led to a decrease in vertical acceleration of up to 0.5, increase in forward speed and, consequentially, automatic retraction of flaps from 15° to 10° at a speed of over 200 knots.  The short-term decrease in engine thrust wihin 3 seconds resulted in decreasing speed and flaps extension to 15°, although the following crew inputs to regain maximum takeoff/go-around thrust led to speed increase and reiterated automatic flaps retraction to 10°. The flaps remained in the latter configuration until the impact.  The pilot flying, by pulling up the control column, continued climbing with a vertical speed of as much as 16 mps.  At a height of 900 m there was a simultaneous control column nose down input and stabilizer nose down deflection from -2,5 deg (6,5 units) to +2,5 deg (1,5 units) (theFDR recorded a nose down stabilizer input from the stabilizer trim switch of the control wheel lasting 12 seconds, while the CVR record contains a specific noise of rotation of the trim wheels located on both sides of the central pedestal), as a result the aircraft, having climbed to about 1000 m, turned into descent with negative vertical acceleration of -1g.  The following crew recovery actions did not allow to avoid an impact with the ground.  At 00:41:49 the aircraft hit the runway about 120 m from the threshold with a speed of over 600 kmph and over 50 degrees nose down pitch.

 

scott s.

.

 

 

Thanks a lot for that report Scott,

 

Unfortunately it's not really clear as to what happened in the seconds before the impact.

 

Apparentlly they accelerated so much during the go-around that the flap load-relief mechanism (what they call "automatic flap retraction") went into action.

 

Controlling the aircraft during very large thrust and configuration changes must be tricky. SPECULATION: The heavy nose-up pitching moment of the GA thrust might have taken the pilots by surprise. /SPECULATION

 

Also they mention a decrease in thrust, but they don't mention how that happened or how large the decrease was.

 

They were trimming nose-down heavily, SPECULATION: could they have been trying to recover from a stall at this point already? How did they get from a flap overspeed to a stall? Windshear maybe? A microburst? /SPECULATION

 

It's remarkable that they mention "column and stab nose down deflection [...] AS A RESULT the aircraft turned into descent". That's interesting, SPECULATION: was the aircraft brought into a descent by the pilots, OR was it descending because of a stall and the crew were trying to bring the aircraft OUT of the stall by pushing the column forward, which is the correct procedure. /SPECULATION.

 

By the way, 16 m/s is 3150 fpm

 

The report in its prompt conclusions doesn't say much other than "practice go-arounds in various conditions". They also mention the Tatarstan 363 and the Armavia 967 accidents.