Posts about: "CCTV" [Posts: 84 Pages: 5]

Having read through most of the posts in this and the other threads, and the preliminary report a few times in parts, am mystified by this:

The Preliminary Report states: "The CCTV footage obtained from the airport showed Ram Air Turbine (RAT) getting deployed during the initial climb immediately after lift-off (fig. 15). No significant bird activity is observed in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall."

Does this mean the RAT deployed "immediately after" in the sense of within 1 second after lift-off?

We, as a group, certainly seem to be interpreting the "immediately thereafter" in a prior paragraph to mean that the E1 and E2 fuel cutoff switches went RUN -> CUTOFF within 1 second or so after max airspeed of 180kts at 08:08:42.

The prior paragraph for quick ref:
"The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off."

Additionally, have to say, this PR has a few major weaknesses in it:
- no timestamp for RAT deployment, though RAT hydraulic power coming online has one; also is it for initial power or rated power?
- no timestamp for the pilot conversation about 'cutoff', though it is provided for the MAYDAY.
- no timestamps for E1/E2 Fuel Cutoff Switches going from RUN -> CUTOFF, though they're provided for CUTOFF -> RUN.

Hi appruser ! I have quoted Pip_Pip 's post above because the position provides a better means to link ADS-B data to the sequence of events, since it's coming directly from the aircraft. The time stamp comes from the volunteer-run receiver, which might experience clock drift. Based on the public CCTV video, we also have a rough triangulation for the rotation, which occurs next to the high-speed turnoff for the third taxiway.

Note that the good folks at FR24 did not apply temperature correction to the barometric altitude (they corrected for air pressure and runway elevation); pilots on pprune have done the corrections themselves and arrived at slightly different values, so take those altitude numbers with a grain of salt. Note also that the 787 sends altitude in 25 ft. increments, and I don't know how these are rounded (up, down, nearest).

We do not know how long the RAT has been deployed in this photo, we only know it can't have been deployed later. I have learned on this thread that the CUTOFF switch will also cause the VFSGs to disconnect, i.e. the B787 systems will electrically isolate the engine from the power buses before it has spooled down. With a dual failure, this would leave the main buses unpowered in short order, so if all of this is correct, the RAT would have clonked into place very soon after the second engine was cut off. This would not depend on the turbine speed.

I personally do not know what items are logged on the flight recorder, but I imagine RAT deployment was not among them. If so, the conditions for its deployment would be logged, but it requires an analytical step to conclude it did, and a preliminary report typically has no analysis at all. Hydraulic pressure to the flight controls is likely logged, so the RAT delivering hydraulic power would be a matter of record.

Where is the RadAlt antenna on a 787? Is it in the nose, or further back between the main gears?

After 9/11, many countries and airlines changed their jumpseat policies, restricting access to the flight deck to active crew members only. That was a knee-jerk reaction. Imagine there had been jumpseaters on the doomed 9/11 flights — wouldn’t they have tried to stop the cockpit intruders? With jumpseaters present, the pilots would at least have stood a better chance of defending themselves and avoiding being overpowered so quickly.

After 9/11, reinforced cockpit door locks were also introduced. But did that really make aviation safer? Consider Germanwings 9525, or MH370. On narrowbody aircraft, these locks don’t even prevent a group of terrorists seated in one of the front rows from storming the cockpit when the door is opened for a meal or a bathroom break. And yet, after GW9525, no one suggested removing the locks — despite the fact that they contributed to that tragedy.

Instead, many airlines — including mine — introduced a policy requiring that no pilot ever be left alone in the cockpit. But to what end? Would a flight attendant really be able to stop a determined pilot from committing suicide? It takes only seconds to shut off fuel control switches, pull engine master switches, and activate fire handles. A flight attendant could just as easily do those things, or take the cockpit fire axe and attack the remaining pilot, then lock the door. How rigorous are the background checks for flight attendants compared to pilots?

And now, in the US, some pilots are even allowed to carry guns in the cockpit. How long before that leads to catastrophe? I fear it’s only a matter of time.

I suspect there will again be knee-jerk reactions to AI171. Perhaps making it harder to operate critical switches? Would that really improve safety? Or installing CCTV in the cockpit? Would that prevent pilot suicide, or simply make it harder to hide? And would the cost and complexity really be worth it?

In my view, the biggest opportunity for improvement lies not in aircraft design, but in human resources. How can we better support pilots who are feeling down, stressed, or depressed? I don’t believe every crash necessarily calls for a technical or procedural fix. In this case, I see no compelling reason to change the aircraft itself.

Of course, the one sure way to eliminate pilot suicide would be to remove pilots altogether and fully automate flight. But I believe it will take a long time before such a system is truly safer than what we have today.

The best course of action for now is the same as in many situations in the cockpit: sit on your hands, resist the urge to act impulsively, and thoroughly investigate what would truly be the most effective response.

In my country, the ministry of transport has adopted the goal of “zero” road traffic fatalities. That’s unrealistic — even absurd — unless you ban all forms of transport altogether.

Perhaps we should acknowledge that not every incident or accident needs to be followed by a remedial action. In the case of AI171, any action we take should focus squarely on human factors.

Thank you for your reply, appruser , and apologies fur cutting most of it:
1. I don't know that the transponder lost power, because I don't have knowledge which electrical bus it is powered from on the 787. It may well have been powered from the main battery the whole time. The FR24 receiver may have stopped receiving data because it could no longer "see" the aircraft‐‐we know there are issues because it didn't even see the eastern half of the runway.
2. Altitudes are rounded, so this could be close to 75 feet gain‐‐or a gain and decline, if the data covers the top of the trajectory.
3. The first reading is definitely in the air, after rotation. FR24 does not report the altitude when the ADS-B data indicates that the aircraft is on the ground, and their data download confirms that.

The best bet to establish timing is to use rotation as datum, and then match the altitude/time estimates from the CCTV with position/time from the ADS-B and the estimated ground speed of the aircraft.

The fact that the ground speed is declining throughout the data sequence strongly suggests that it begins some time after the point, or at the point, when thrust was lost. And we know that didn't begin to happen until the aircraft was 3 seconds into the air.