Polish President and wife killed in Tu-154 crash

[Gabriel]

Another part:

Could the Tu-154M crew descend below the altitude set for 100m? – The Russians seem to be trying to hide the fact that it is not possible according to the manual of autopilot (Flight Managing System by Universal Avionics UNS-1D) – the pilots stated. The crew sets the target altitude for 100m. The autopilot will not descend below this altitude. It is hard to deduct from the CVR transcript which functions were set on the autopilot. The SOP manual for Tu-154 states that after reaching the target altitude, the captain has 3.5 seconds to make the decision about landing. And he can do it only if he can see the ground. If that’s the case, he switches to manual mode. If it’s not the case, he pushes the „go around” button which causes the autopilot to apply the take off thrust and ascend to 500m altitude. The autopilot was not turned off, so there was no intention to land.

Three things:

1- I won't take what the SOP says as evidence of what they were doing. In many cases, accidents happen precisely when the SOP is not followed right.

2- There might be reasons why the autopilot won't climb despite its "intentions". Insufficient airspeed is one of those. (however, unless the plane has some sort of envelope protection, this will typically lead to a stall, and I've heard nothing about a stall here yet).

3- How's that that the AP was not turned off? I'd have to check, but I remember that the CVR had the crew turning it off at some time.

[Northwester]

Three things:

1- I won't take what the SOP says as evidence of what they were doing. In many cases, accidents happen precisely when the SOP is not followed right.

2- There might be reasons why the autopilot won't climb despite its "intentions". Insufficient airspeed is one of those. (however, unless the plane has some sort of envelope protection, this will typically lead to a stall, and I've heard nothing about a stall here yet).

3- How's that that the AP was not turned off? I'd have to check, but I remember that the CVR had the crew turning it off at some time.

1- Agree
2- Hard to say yet
3- They turned it off just few seconds before the crash when they tried to recover

[Gabriel]

3- They turned it off just few seconds before the crash when they tried to recover

Hmmmm... Interesting.
Of course the AP will still descend below the MDA if you told "him" to do so. Or it could be tha "lack of airspeed" thing. Or a systems malfunction.

We need the FDR now! (not that that who has it will care, of course)

[Northwester]

One more piece:

Experts point to strange TAWS announcements. At 10:39:57.1 the plane is at alt 400m. But just 3 seconds after TAWS alerts “Terrain Ahead”. This alert is incorrect. It can mean some kind of malfunction. There are 4 possibilities: the navigator did not set TAWS (the transcript confirms that TAWS was set), the plane was 250m lower, the info about TAWS is not correct, or TAWS was not working properly. Five seconds before the end of the recording TAWS does not finish the last alert. Pilots point that this is highly irregular for TAWS always finishes an alert.

[Northwester]

And another:

Credibility of MAK’s transcript is undermined by a lack of voice identification authorization and a lack of signature of one of the representatives of Polish side – col. Bartosz Stroinski. He was the only person responsible for voice identification. MAK has not included the name and details of the lab that processed the recording. There is no info about the condition of the recorder, condition of the tape (any damage and to what extent) and the condition of the recording itself. Such info has to be a part of any crash report.

[Northwester]

About autopilot:

This is how AP was set (based on navigator’s statements):
- auto navigation – keeping course in horizontal plain, course on RWY 259 deg.
- auto altitude control – maintaining the path in vertical plain, angle of descent 2 deg, variable
- Way-Points on path (5 consecutive every 2 km)
- target altitude 100 m - autopilot does not go below it
- auto thrust with preset airspeed TAS=280 km/h (autopilot maintains speed +/- 10 km/h, average thrust at 28% of takeoff thrust

[Curtis Malone]

Another part:

Could the Tu-154M crew descend below the altitude set for 100m? – The Russians seem to be trying to hide the fact that it is not possible according to the manual of autopilot (Flight Managing System by Universal Avionics UNS-1D) – the pilots stated. The crew sets the target altitude for 100m. The autopilot will not descend below this altitude. It is hard to deduct from the CVR transcript which functions were set on the autopilot. The SOP manual for Tu-154 states that after reaching the target altitude, the captain has 3.5 seconds to make the decision about landing. And he can do it only if he can see the ground. If that’s the case, he switches to manual mode. If it’s not the case, he pushes the „go around” button which causes the autopilot to apply the take off thrust and ascend to 500m altitude. The autopilot was not turned off, so there was no intention to land.

Minor problem: the UNS-1D is NOT the autopilot, it's the FMS, from which the autopilot gets information, but is not the autopilot itself.

[Evan]

About autopilot:

This is how AP was set (based on navigator’s statements):
- auto navigation – keeping course in horizontal plain, course on RWY 259 deg.
- auto altitude control – maintaining the path in vertical plain, angle of descent 2 deg, variable
- Way-Points on path (5 consecutive every 2 km)
- target altitude 100 m - autopilot does not go below it
- auto thrust with preset airspeed TAS=280 km/h (autopilot maintains speed +/- 10 km/h, average thrust at 28% of takeoff thrust

The transcript is more like sanskrit to me (is there still no full-text transcription of those cryptic photocopies on-line?), but I don't really see any conclusive indication that they were using the autopilot, only that is was armed for go-around.

Can anyone decipher this? The CAPT is indicating something without automation:

10:31:01.0 Nav: Yyy... piatka, szóstka, automat ciagu.

10:31:03.9 Capt: Piatka, szóstka przygotowane i zostaje bez automatu.

[Evan]

Also, there is this seemingly confusing exchange about flaps:

10:36:34.1 A: Klapy.

10:36:35.3 F/O: Klapy 28 (niezr)

10:36:36.9 - 10:36:56.4 A: (niezr), (7 statements over 20 seconds)

10:37:02.3 CAPT: Klapy.

10:38:37.3 CAPT: Klapy 3-6

10:38:51.9 F/O: I Klapy 36, mamy 2-8-0

10:38:56.6 F/O: (niezr)

10:38:57.2 CAPT: już. (does this mean "now", "right now" or already"?)

10:38:59.0 F/O: Klapy 36.

10:39:02.2 NAV: Kabina, Sterowanie przednim podwoziem mamy wlaczone. Mechanizacja skrzydel.

10:39:07.5 (Unidentified) Mechanizacja skrzydla przeznaczona jest do (niezr). {Glos w tle czytania karty - gen. Blasik.}

10:39:09.6 CAPT: Klapy 36.

[Northwester]

The transcript is more like sanskrit to me (is there still no full-text transcription of those cryptic photocopies on-line?), but I don't really see any conclusive indication that they were using the autopilot, only that is was armed for go-around.

Can anyone decipher this? The CAPT is indicating something without automation:

10:31:01.0 Nav: Yyy... piatka, szóstka, automat ciagu.

10:31:03.9 Capt: Piatka, szóstka przygotowane i zostaje bez automatu.

10:31:01.0 Nav: Aaa... five, six, thrust on auto.
10:31:01.9 Cpt: Five, six ready and without auto thrust.

According to pilots comments, five and six refer to navigation settings. And the captain decided not to set the automatic thrust yet. He switches to auto at 10:34:21.5.

[Northwester]

Also, there is this seemingly confusing exchange about flaps:

10:36:34.1 A: Klapy.

10:36:35.3 F/O: Klapy 28 (niezr)

10:36:36.9 - 10:36:56.4 A: (niezr), (7 statements over 20 seconds)

10:37:02.3 CAPT: Klapy.

10:38:37.3 CAPT: Klapy 3-6

10:38:51.9 F/O: I Klapy 36, mamy 2-8-0

10:38:56.6 F/O: (niezr)

10:38:57.2 CAPT: już. (does this mean "now", "right now" or already"?)

10:38:59.0 F/O: Klapy 36.

10:39:02.2 NAV: Kabina, Sterowanie przednim podwoziem mamy wlaczone. Mechanizacja skrzydel.

10:39:07.5 (Unidentified) Mechanizacja skrzydla przeznaczona jest do (niezr). {Glos w tle czytania karty - gen. Blasik.}

10:39:09.6 CAPT: Klapy 36.

10:36:34.1 A: Flaps.
10:36:35.3 F/O: Flaps 28 (rest not understood)
(Flaps are lowered to 28 deg.)
10:36:36.9 - 10:36:56.4 A: (niezr), (7 statements over 20 seconds)
(Pilots find it strange that such a long section is missing entirely)
10:37:02.3 CAPT: Flaps.
10:38:37.3 CAPT: Flaps 3-6
(Flaps lowered to 36 deg.)
10:38:51.9 F/O: And Flaps 36, we have 2-8-0
(According to pilots, at the crash site the flaps were at 28 deg. Here they say the flaps are still at 28 deg.)
10:38:56.6 F/O: (not understood)
10:38:57.2 CAPT: right away
(Can also mean "done already")
10:38:59.0 F/O: Flaps 36.
10:39:02.2 NAV: Cabin, front wheels steering turned on. Mechanization of wings.
(Navigator reads from the check card)
10:39:07.5 (Unidentified) The purpose of wings mechanization is (not understood). {Voice in the background of reading the card - gen. Blasik.}
10:39:09.6 CAPT: Flaps 36.
(The flaps are lowered to 36 deg.)

[Evan]

10:31:01.0 Nav: Aaa... five, six, thrust on auto.
10:31:01.9 Cpt: Five, six ready and without auto thrust.

According to pilots comments, five and six refer to navigation settings. And the captain decided not to set the automatic thrust yet. He switches to auto at 10:34:21.5.

10:34:21.5 CAPT: Automat.
10:34:23.9 Flight Engineer: I automat wlaczony.

Are you sure that refers to autothrust? Why is the flight engineer responding to that command?

[Evan]

10:38:37.3 CAPT: Flaps 3-6
(Flaps lowered to 36 deg.)
10:38:51.9 F/O: And Flaps 36, we have 2-8-0
(According to pilots, at the crash site the flaps were at 28 deg. Here they say the flaps are still at 28 deg.)

I assumed that was 2-8-0 airspeed in km/h. I don't know the vfe values but it seems about right, doesn't it?

But were the flaps ever lowered to 36? There seems to be a strange confusion, including a bizarre declaration from someone on the purpose of flaps. (For what little it might be worth, the TU-154M was the first to have a flaps 36 setting). It's also possible that if the flaps were found at 28, they may have been retracted from 36 in the final moments.

Essentially, this cvr transcript is a puzzling mess. There must be omissions. Hopefully, we will one day see a corrected version.

[guamainiac]

Of particular interest here to understand thing would also be the tone and volume of the narrative.

What parts are in a "command voice" and which are routine or conversational or interrogatory?

Or, as a Hawaiian fellow said once to me, it's not that I call you "haole", it's the tone used. In the wrong place you may want to run.

[Northwester]

10:34:21.5 CAPT: Automat.
10:34:23.9 Flight Engineer: I automat wlaczony.

Are you sure that refers to autothrust? Why is the flight engineer responding to that command?

The Flight Engineer needed to unblock throttle so the autopilot could take over.