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-   -   Iran Accident (https://www.pprune.org/rumours-news/605571-iran-accident.html)

Carbon Bootprint 19th Feb 2018 20:05


Originally Posted by DaveReidUK (Post 10057310)
Reportedly WFU due to shortage of spares.

Can you name the source? I'm not meaning to sound doubtful and all, but that is a lot of time for bird to be on the ground if it wasn't properly looked after. Thanks.

txl 19th Feb 2018 20:46

Re: Source

The Guardian reports, citing Iranian media:


An Iranian news website said the plane had recently rejoined the air fleet after seven years of undergoing repairs. “The plane which crashed today faced technical problems midair during a recent flight a few weeks ago,” Roozarooz news reported.

An Instagram post from Aseman Airlines two months ago that announced the plane was back in service after seven years was deleted this morning after the plane crash, Roozarooz reported.
Also, see the tweet by Iranian Aerospace Talk Forum I cited above. This could be sourced from the allegedly deleted instagram post.

RatherBeFlying 20th Feb 2018 00:27

The missed approach from MDA demands accurately tracking an NDB back bearing. Not every ADF installation does back bearings as well as front bearings.

How many crews today can do a good wind correction on an NDB bearing?

Was there any calibration flown on the approach?

Even more exciting would be flying a missed from as much as 4000' below the MDA. Was calibration for the missed flown from just above the runway?

aterpster 20th Feb 2018 00:52


Originally Posted by RatherBeFlying (Post 10058663)
The missed approach from MDA demands accurately tracking an NDB back bearing. Not every ADF installation does back bearings as well as front bearings.

How many crews today can do a good wind correction on an NDB bearing?

The old salt Russians. Dual ADFs on RMIs.


Was there any calibration flown on the approach?
Only Iran knows that.


Even more exciting would be flying a missed from as much as 4000' below the MDA. Was calibration for the missed flown from just above the runway?
That might not be part of Iranian flight inspection specs. Or, many other countries for that matter.

I believe the recent installation of the VOR/DME is evidence that Iran was on the path to improvement at this difficult airport.

ThreeThreeMike 20th Feb 2018 04:02


Originally Posted by Hotel Tango (Post 10057506)
We don't know yet of course but I would very much doubt that aircraft serviceability had any role in this. More likely a scenario relating to weather and procedures.

I agree with you.

The economic sanctions placed on Iran years ago caused quite a few aircraft to be sidelined.

Kulverstukas 20th Feb 2018 12:57

TEHRAN, Iran (AP) - Iranian search-and-rescue teams on Tuesday offered the first images of the site of an airplane crash in southern Iran that killed 65 people, with officials hoping to reach the aircraft's "black boxes" to learn exactly what downed the flight.

State television aired footage showing the plane crash site against the side of a snow-covered mountain near Yasuj, some 780 kilometers (485 miles) south of Tehran, Iran's capital from which the Aseman Airlines flight took off on Sunday.

A helicopter pilot interviewed by state television said the crash site appeared to be only 30 meters (100 feet) from a peak on Mount Dena in the Zagros Mountain range.

"Some large parts of the plane, which were labeled with the Aseman company logo, were seen," said the pilot, identified by state TV only as Capt. Soheili.

A0283 20th Feb 2018 13:26


the wreckage had been found through drone images before the air force's helicopters were deployed.
From now on drone deployment appears to have become a standard tool in both SAR and investigative efforts. Similar use in the Antonov case. And especially helpful in difficult conditions ... Like the high snow in these two 2018 cases. In this case the helicopters could not land and people on foot are the only option. Drones make a search far more efficient and effective which is a great help for those in SAR and contributes to their safety.

G-CPTN 20th Feb 2018 14:03

What size of drone?
Are we talking 'pilotless aircraft'? - or a portable toylike device?


Edited to add:-

The wreckage was finally spotted by a military drone

twistedenginestarter 20th Feb 2018 14:11

NDBs?
 

Originally Posted by RatherBeFlying (Post 10058663)
Not every ADF installation does back bearings as well as front bearings.

They are Non Directional Beacons, surely?

aterpster 20th Feb 2018 15:20

Blockage by terrain could limit the use of an NDB. Flight inspection has to verify signal strength for both the approach and missed approach. A weak signal can cause a false bearing.

It will be interesting to learn whether the flight flew the procedure correctly to well below MDA, then did a missed approach.

Timmy Tomkins 20th Feb 2018 15:49

It's hard not to feel for this crew. Who knows if they pushed limits but the captain was a veteran and presumably familiar with both airport and the limitations of the approach; as sad end to what was probably a distinguished career.


Not the type of approach facility I would want to deal with in those conditions; especially when they could have had a VOR DME approach there. Was there radar cover in the area or where they expected to let down using own nav? That could explain the end result if the aircraft only had basic kit.

albatross 20th Feb 2018 16:32


Originally Posted by RatherBeFlying (Post 10058663)
The missed approach from MDA demands accurately tracking an NDB back bearing. Not every ADF installation does back bearings as well as front bearings.

How many crews today can do a good wind correction on an NDB bearing?

Was there any calibration flown on the approach?

Even more exciting would be flying a missed from as much as 4000' below the MDA. Was calibration for the missed flown from just above the runway?

An ADF That doesn't allow tracking outbound from the NDB?
How the heck would you do an NDB approach?

JW411 20th Feb 2018 17:02

I think the poor chap is getting confused with a Back Course ILS. He obviously has never flown an NDB let down in his life (unlike me).

Patanom 21st Feb 2018 02:09

2 Attachment(s)
Europian Datum 1950 is using in Iran. The height difference from WGS-84 is 30.24 meters.
Therefore, I think it started to decline about 1 km earlier. The distance along the axis of the runway differs by approximately 60 meters (2 arc seconds).
Sorry, the distance along the axis of the runway differs by approximately 30 meters ( abt 1 arc seconds).

Plumb Bob 21st Feb 2018 03:13


Originally Posted by aterpster (Post 10057104)
Jeppesen has only two charts. [...]

On that approach chart 16-1 (dated 20 Oct 17) the minimum altitude during the teardrop turn is given as 12,500 for category A and B aircraft, but 11,400 for the faster C and D categories. I would expect that to be the other way around, i.e. the higher altitude for the faster airplanes with their wider turning radius, as well as their outbound course that is aimed closer to the mountain range in the east.

aterpster 22nd Feb 2018 00:44

That occurred to me, too. It would be interesting to see state source; i.e., the official Iranian chart in their AIP. I doubt that is available on-line, though.

Jeppesen is careful, but not perfect.

In any case, the accident did not occur in the area of the base leg.

galaxy flyer 22nd Feb 2018 02:57

Actually, the Iran AIP is online, but I couldn’t access the charts on an iPad, requires desktop.

ironbutt57 22nd Feb 2018 04:35

They are Non Directional Beacons, surely?

not the onboard equipment

Machinbird 22nd Feb 2018 05:24

Everyone is discussing the interesting approach, but it is not clear to me that the aircraft even reached the Yasouj NDB to commence the approach.

Those are some serious Mountains north of Yasouj, and tall mountains, strong winds can create extreme problems in maintaining altitude.

So far, information on the route of the flight has been pretty sketchy. :confused:

JW411 22nd Feb 2018 08:22

ironbutt57:

Exactly so; the NDB is the bit on the ground and the ADF is the bit in the aircraft.


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