The FDR data should answer this question, I tried looking it up but didn't find an answer:

If the gear handle is lowered above 260kts the gear will not extend. If the handle is left down and speed slows below 260 does the gear then extend or does the handle have to be moved up and then back down to reset the logic?

Would seem a little dumb to me if they had the handle down and were slower than 260 but the gear never came down.

Previously answered.

quote:

The gear handle sends an electronic signal to sequence hydraulic valves for gear operation: down or up. The hydraulics to move the gear are locked out above 260 knots.

But is there a time limit to being below 260 kts, or does it only require an instantaneous dip below 260?

No, there's no time limit. 260 knots is 10 knots above the maximum gear operating speed. The lockout is 260 +/-5 knots. The only thing that happens at that point, if the gear handle is placed in the down position, is that the hydraulic power source for actuating the gear is locked out by a valve. When below the lockout speed, the valve is opened if the gear handle is down. Once the down signal is given, once the pressure is available, the gear is hydraulically unlocked, allowing it to gravity fall, with aerodynamic assistance. There is no signal associated with 260 knots which causes a gear retraction. Once it starts down, it's down. The limit with gear extended then becomes 280 knots.

The maximum speed for gear retraction is 220 knots. If the crew intends to retract the gear, they'll need to reduce speed below 220 knots and place the gear handle in the up position.

Whoa, not even Juan Brown knows the answer whether the landing gear will automatically deploy if the safe speed threshhold is crossed. Skip all the way to the end @20:00...

I touched on this earlier.

The issue has many facets. In some aircraft/systems, there are design and operations that can result in a myriad of outcomes.

For example, an aircraft may have WOW (Weight on/off Wheels) switches that either lockout or enable a specific outcome when the switch is energized/de-energized.

Such results may be a direct design implementation to ensure a specific outcome to the switch actuation.

Some switches may ensure that fuel pressurization of external stores does not begin until the aircraft has lifted off the runway and that the same pressurization of external stores is terminated when the gear is down, and/or the weight of the aircraft upon landing, dumps/stops pressurization.

Similar is the lifting of the gear handle on takeoff roll, and the gear will not begin initiation to "raise", until the weight is off, (the struts extend to the full limit, and the "squat" (WOW) switch is energized) allowing the gear to begin retraction. (This was/is done to prevent over-speed of gear on many fighter-type aircraft, due to the rapid acceleration after rotation, and the various requirements required during climb out with "cleaning up" and post-departure tasking of the pilot.)

But, the more things are "automated" the more likely aircrew is likely to "miss" an automated event that fails to occur.


To have a system that if the gear extension is done above the limit, then allowing the gear to drop when the "within limit" airspeed is met, might be a normal condition, for example:

An aircraft is on final and drops the gear 10kts above the "limits", the gear will not drop, ten seconds later, the aircraft is now below that upper limit of gear deployment, and the gear drops and locks, the landing approach continues without issue, and life is good.

Now, (speculating) if an aircraft has attempted to lower the gear say 10kts above the "limit", the gear does not drop, and a missed approach is initiated, (the aircraft never drops below the limit that would allow gear extension) and the gear handle is still in the "lowered" position. Then for whatever reason, loss of thrust condition is encountered, and at a point that is critical, the airspeed falls below the "gear lowering limit" and the gear drops, the increased drag will be very significant and if the "loss of thrust" is due to engine failure, the hydraulics will also be diminished or lost and the likelihood of effective hydraulic pressure to raise the gear, unlikely.

When you need the least amount of drag, you will have the worst amount of drag.

Not a good place to be.

Always looking to fault the aircrew, or the maintenance folks, who often have a lot of skin in the game, (instead of some fat assed engineer, sitting in a chair designing systems and all snug in his bed) while folks are screaming the last seconds of their lives, or some maintenance puke, living life wondering if they missed a procedure, is a pathetic after-action report.

Engineers need to embrace the folks that operate and maintain the platforms.

(system operations/procedures and the results, should not require a great deal of thought/guesswork/analysis from those who rely on them functioning in a manner that will not lead to their death when initiated)

I'll stop, before this turns into a rant...

Airbus has a long litany of laws and conditions that have proven obstacles to the ability to recover, and have on occasion, proven fatal.

Pakistan has a culture of privilege and politics, in which the pilots are not the competitive vetted, but are often the incompetent or fruit of nepotism and dropped names. Like India, it's a land where even the private pilots call themselves "wing commander," and invariably run when they should crawl.

For some, the airbus represents a compromise to help keep the pilot from breaking the airplane. The concept behind the airbus system, after all, is largely pilot-proofing the airplane. In the old analogy of the dog in the cockpit, which is there to bite the pilot if he tries to touch anything, the airbus is the dog.

When the most basic tenets of flying are violated, such as the stable approach, then all else is long gone out the window. The crew never got the gear down, and were too busy trying to get down, rather than preparing to land.

Eastern Airlines L-1011 Flight 401, 1972.
Crashed in the Florida Everglades while the entire cockpit crew dicked around with a nose landing gear indicator bulb problem.

While trying to replace the bulb, the autopilot was inadvertently disengaged, and the Second went "downstairs" (in the "hell hole") to verify the NLG condition being down and locked or unsafe, and no one heard the chime at the Second's station that "low altitude" condition existed.

That was one event that always stuck with me.

Sort of like "target fixation", and the two types of mishaps always made me wonder how one could get so caught up/distracted, that they put a perfectly flyable machine (and people) into the ground.

My heart goes out to those who have had a shit hand dealt at the most inopportune time, like the 1978 DC-10 at O'Hare on takeoff, due to shitty maintenance, or the guys in the 747 in the sandbox when the load broke loose and screwed the aft GC beyond limits.

You know, that they knew, and was nothing they could do, but bet they tried it all on the way in.

Being "the monkey on a rope in the back", there are a few times that I know my ass is still here because the guys up front had their shit wired right.

And nothing worse than those guys (and the folks relying on them) getting a shit hand dealt with them by someone else, who likely lives a long life after the fact.

I would rather have someone who knows a thing or three about flying, than someone who has been given a few Scoobie Snacks as a reward for pushing a button when the light blinks.

I like old school. (and I also appreciate innovations and better/safer ways of keeping airchines out of the dirt.)

Lots of nickels...

Severe blue and calm condisions to you.

quote:

Eastern Airlines L-1011 Flight 401, 1972.

Ooh, I remember that one, Sigmonkey. A burned out 20 cent bulb and a lot of distraction cost 96 lives.

quote:

Originally posted by sigmonkey:

Always looking to fault the aircrew, or the maintenance folks, who often have a lot of skin in the game, (instead of some fat assed engineer, sitting in a chair designing systems and all snug in his bed) while folks are screaming the last seconds of their lives, or some maintenance puke, living life wondering if they missed a procedure, is a pathetic after-action report.

Engineers need to embrace the folks that operate and maintain the platforms.

What makes you think we don't? We ride on these planes too, along with friends and family.

It seems really clear that the aircrew is at fault here. NOTHING about the approach that was flown is even remotely reasonable, or "by the book". Go take your blame game somewhere else.

Truth of the matter is those Pakistani pilots sucked ass from start to finish.

Oh, this system did this, this system did that. Give me a fooooking break.

They put themselves and a perfectly good airplane high, fast, and steep - then exceeded their minimal piloting capabilities in trying to 'make it happen' instead of taking a lap around, getting their shit sort of together, and making a reasonable landing attempt.

quote:

Originally posted by kkina:
Whoa, not even Juan Brown knows the answer whether the landing gear will automatically deploy if the safe speed threshhold is crossed. Skip all the way to the end @20:00...

Juan may not know, but if the gear handle is placed in the down position and airspeed lowers below 260 (+/- 5) knots, the hydraulic lockout is opened, and the gear will drop, as already described.

Thank you. I did read through your explanation, but was still unclear how the whole thing worked.

At any rate, is it then possible they tried to land at a speed above 260 knots?

quote:

Originally posted by kkina:
At any rate, is it then possible they tried to land at a speed above 260 knots?

If so, a true indication that the pilots had no right to be behind the controls of a Cessna 150, much less an A320 with pax onboard.

The Flight Data Recorder will tell the true tale at some point.

In theory one could attempt to land at that speed, but there are several key considerations. In order to land at any airline in the world, stable approach criteria must be met, at a minimum, by 500' above the airport elevation, and in most cases 1,000 to 1,500. They weren't stable.

In order to land, the airplane must be configured. that means gear and flaps, and settings established for brakes, spoilers, etc.

Landing performance is based on a particular weight and configuration, as well as temperature, runway conditions, etc. If one is at all faster than the speed established for that performance evaluation, then one is going to either floating down the runway (they did) or landing long (they did), and most importantly, not stopping in the distance planned. Any extra speed means a lot more stopping distance, hotter brakes, etc. Consequently approach speed is flown precisely, and any extra speed results in a long float. To hit the end of the runway at 260 knots and to attempt to bleed off the speed at that point would mean doing so in ground effect and a runway more like something found at Rogers dry lake bed at Edwards AFB (space shuttle landing site. Still probably not long enough. The crew would get the aircraft to the point of anticipated landing, and it wouldn't be ready to land. They'd have to force it onto the runway.

Autothrottles and other components take their cues from several sources and without the criteria necessary for them to operate in a particular phase of flight, they also present problems that may range from not being operative to the need to manually disconnect.

There are cockpit aural warnings for incorrect configuration which can be cancelled in some, but not all situations. They are not subtle and they are unmistakable. They're loud.

Warnings occur in various combinations. Insufficient power setting with no gear, a warning that can be cancelled. A landing flap setting with no gear, it can be cancelled, except below a specific altitude, and so on. The warning is there to alert the crew to no gear, as are additional displays and warnings visually, and certain warnings that can be cancelled, will reoccur each time the power is reduced below a certain point.

Prior to landing a descent and approach checklist must be completed, as must the before landing checklist, and confirmed by both crew members (and typically any additional company crew on the flight deck (or certain parts of the checklist by additional crewmembers; clearances, run way confirmation, etc). Absence of that clearance and the final statement ("Before Landing Checklist Complete"), along with an acknowledgement of that completion (in accordance with the individual operators standard operating procedures and standard callouts)...isn't something one would normally just skip past.

Most operators also have a stability statement somewhere in the approach; most require that the aircraft be fully configured before reaching the final approach fix or glideslope intercept point, and then by 1,000' a statement by one or both crew that the aircraft is stabilized and that no new alerts have been received.

There's more, but the bottom line is that there are a lot of checks that must be executed and satisfied prior to landing, making the notion of arriving at the runway unstable (fast being unstable) and unconfigured, and with the intent to land, all the more perplexing. It's a truly WTF? conundrum.

Add external warnings to the mix; in the US and abroad military controllers will advise the pilot to confirm that the landing gear has been extended. Foreign controllers and civil US controllers usually don't do that, but most tower controllers will be looking, all the same, and should there be a problem, it would be incumbent on the tower controller to advise the flight to go around.

Having said that, at some Islamic locations, I have spoken with the controller when approaching the airport or getting established on the instrument approach, only to have radio silence. I have landed and located the controller either asleep, or praying, having quit controlling while I'm in the middle of approaching to land...so a controller in these locations that didnt notice the gear wouldn't be that surprising. The controllers did, however, assign the pilot a turn off course, as they recognized that the pilot had a high rate of descent and wasn't stable on the approach.

I have arrived in Karachi in the past, dumped high by the enroute controller, and have been asked by the Karachi controllers if I can get down in time, or if I need a turn to get down. In this case, the Karachi controller advised the PIA flight to take a vector, or a heading, in order to give the pilot more time to get set up to land. The PIA crew refused the vector and continued, unstable, to their gear-up event.

Is it possible to land at 260 knots? In theory, yes, but pretty damn difficult.

The preliminary report was published today. The crash was attributed primarily to human error, the pilots and also the Air Traffic Controller. The CVR revealed that distraction was a major factor due to the pilots discussing the coronavirus at a time where full focus should have been on the landing operation.

Can a pilot (or anyone else) explain why the landing gear was lowered at around 10.5 nautical miles, then subsequently raised less than 5 NM from the runway?

Full Report

^^^^^
I believe it's been answered that with the gear handle in the DOWN position, they were going too fast, even in their 3 "skip-n-go's" on the runway, for the gear to deploy. It wasn't until after the ill-fated go-around that they were slow enough for the gear to extend.

Anyone?

Just leave the gear down all the time to eliminate confusion.

Always the best pilots.

quote:

Originally posted by erj_pilot:
^^^^^
I believe it's been answered that with the gear handle in the DOWN position, they were going too fast, even in their 3 "skip-n-go's" on the runway, for the gear to deploy. It wasn't until after the ill-fated go-around that they were slow enough for the gear to extend.

Anyone?

That was a theory from TheFlightChannel that is not supported by the FDR/CVR data released today. According to today's preliminary report, landing gear were lowered about 10.5 NM from the runway on the plane's initial approach, and then inexplicably raised less than 5 NM from touchdown. The gear lever was in the UP position.

Also strangely, immediately after re-raising the LG, the speed brakes were retracted. This triggered the over-speed and EGPWS warnings to sound (f). Why would the pilots do this? They burned in at 220 knots (i).

(The FDR logged a second brief attempt to lower the gear lever during the aircraft's second doomed approach, but the lever was immediately returned to the UP position [UPDATE: Apparently the plane crashed with the landing gear extended. Probably a gravity drop since the hydraulics were probably not working]. (k) I'm guessing the extra drag was immediately apparent on a plane struggling for height.)

This message has been edited. Last edited by: kkina,

Well...I wish I could find a good 8-10 second clip of Gunny Tom Highway telling the General, "It's a Cluster F*ck, sir", because THAT is exactly what those two friggin' knot-heads created. CRM, anyone?? Yeah...I guess THAT dawg don't hunt "over there".

In all honesty, I wouldn't put my dead cat's ashes on a PIA flight. I had a student from Pakistan who's intent was to get through his Commercial/Multi-Engine Certificate and then go back to PIA where his brother was a CA on a B737...I think it was a 737. At any rate, PIA's training program is to take these "newly certificated" pilots and put them through ab-initio training. That training curriculum and method, IMHO, sucks the sweat off a dead man's balls (to quote "Good Morning Vietnam").

I'm here to tell you. While working on his Private Pilot Certificate, that friggin' idiot couldn't fly from Hooks airport in Spring, TX to Lone Star Airport, that's RIGHT NEXT TO LAKE CONROE, without getting lost 4 or 5 times and NEVER finding the damned airport by the BIG LAKE!! You couldn't tell him ANYTHING. And don't DARE tell a mid-easterner they MUST do something (as in study and prepare), because they will absolutely defy you and not care if it "short-dicks every native in the Congo" (to quote Gunnery Sgt. Hartmann) and do what you ask when THEY are damned good and ready. So if THAT is the caliber of pilot PIA hires due to nepotism, it will be a FREEZING day in hell before my ass is strapped to one of their seats in the cabin.

It's a wonder something like this doesn't happen on a regular basis over there...