Luxair emergency at Sarrebruck
 

Luxembourg press reporting Luxair Bombardier Q400 emergency undercarriage up landing at Sarrebruck Ensheim airport this morning. Reported as experiencing sudden heavy smoke (not clear where) leading pilots to decide on emergency return and landing. No injuries reported.

Saarbruecken is the correkt spelling, or EDDR

jacdec.de

Just depends which language you're using. Pleased that all on board are OK.

For photographs go here RTL.lu - Lëtzebuerg - Luxair-Maschinn brécht Start of a kënnt um Bauch un d'Halen

Aviation Safety Network reporting that there was smoke in the cabin immediately after take-off and wheel retraction. A/c landed back on the runway wheels-up.

Seems that retraction was pretty smart for that to have happened, or am I misreading it? (disclaimer, very occasional SLF here)

ASN Aircraft accident de Havilland Canada DHC-8-402Q Dash 8 LX-LGH Saarbrücken-Ensheim Airport (SCN)

Here's an odd case where being gear up may have helped the outcome.

If the gear had still been down when they rejected, being well past V1, if the gear holds then it's probably a high speed overrun. If the gear folds up from the hard landing then it might puncture full wing tanks or cause some spinning or cartwheel action from digging into the ground.

The gear generally are raised smartly after lift-off, to 1) reduce drag and improve climb as soon as they are no longer needed, and 2) get the gear and doors stowed before the dynamic pressure of the airspeed gets too high. It puts more and more strain on things "hanging out," and the actuators that move them, as speed increases.

Without getting into the minutiae of specific aircraft, equipment, operator and pilot SOPs - the pilot not flying (therefore monitoring) has his eyes on the altimeter and vertical speed gauge and calls "Positive rate (of climb)" as soon as the needles indicate such, followed immediately by the call (and action) "Gear UP!"

Has anybody considered the posibility that the gear was retrackted to early and that the aircraft just setteled down on the runway? Not familier with the type, but could it be that the gear handle was in the up position on the ground by mistake and that as soon as WOW occured the gear retrackted and the tail hit followed by the rest of the aircraft?

We have seen the above scenario on the F-16 where the flaps are retrackted automaticly with the gear, and if this is done to early ie. just after rotation, the reduced lift will cause the aircraft to sink back on the runway.

While the scenario You offer would be technically possible, there would have to have been a lot of previous SOP breeches and much negligence for it to occur.

First of all, during the cockpit preparation, among many others the correct positioning of the gear lever and the serviceability of the light bulbs is verified.

Secondly, it is very hard to overlook the gear lever if it is selected UP on the ground, as the wheel-shaped knob on the lever would be lit up (TRANSIT indication, showing that the landing gear is not in the position selected by the lever). To assume that both pilots willingly accepted such an indication and not only taxi, but also take off with this would stretch my imagination a lot.

Also, on the DH8, the flaps are selected separately from the gear and under no circumstance will retract automatically. A too early gear retraction might possibly cause a tailstrike, but (without having tried this!) I would assume that the aircraft is sufficiently powered to climb out of such a situation - even more so with only 16 pax on board and a probably light fuel load.

Tu.114 I know you also have some Q4 time under your belt, I couldn't help but wonder on a 2000m runway, even with 16 passengers on board, I don't think you would be able to take off, climb to a normal sort of height to retract gear and then reverse the aircraft and land.

Which leads me to suspect either the gear was retracted early, or was being retracted as the decision to land was made.

Happy conclusion in that no one died, but lots to come from this I think!

Yes, I too think that the report on this accident will be an interesting read when it comes out.

Pitch after liftoff increases rather quickly. During gear retraction, I would expect to see about 10°; with a light DH8-400, a pitch of 15 to nearly 20° is not uncommon then during initial climb. This means that the runway gets invisible below the nose structure rather soon. Were one to lower the nose again and pull the power levers back with the possible intention to land, there might well follow some surprise about how little runway is still left out of the 2000m.

I do not know but would be interested to learn the following: How will the PSEU (Proximity Switch Electronics Unit, governing and sequencing the gear retraction and extension among many other things) react to a "GEAR DOWN" selection while it still is busy retracting said landing gear?

Either it will simply reverse the process and reextend the gear starting from where it happened to be interrupted in the retraction, or it will complete the retraction and follow with an extension from the fully retracted position - or, the nastiest possibility, it will lock up and produce a "LG INOP" caution light, seeing that the gear is in a not clearly defined position while it still is in movement (a similar PSEU fault has once caused me the need for an alternate gear extension). Is anybody able to shed some light on this?

Dont have any detailed system knowledge to add I am afraid but looking at some of the pictures there is something that looks like an open nosegear door visible?

Burst tire?
 

Hello,

Media report now citing passengers who claim tire burst just before lift-off with aircraft "veering out of control and impacting runway" and pilots then regaining control and putting aircraft down with gear retracted. Aircraft apparently came to a halt 300m beyond end of runway on a paved area of the airport. As with all passenger eyewithness report, not sure how credible.

Report (in German) here: Tageblatt Online - Alle raus! - Nachrichten

Sorry but some things do not make sense to me...

There is mention of smoke from the rear part of the galley just after liftoff, but it would have taken at least 10 seconds for that evaluation to reach the cockpit, then why when airborne decide to dive and crash the aircraft gear up with no guarantee of remaining in the airport/runway perimeter while a traffic pattern on a turboprop will maybe take max. 4 minutes to complete if the situation is immediately so dire...?!

I see no damage hinting of a massive fire at the back?...

Despegue, this is the elephant in the room indeed.

There are two smoke detector circuits on the DH8D that report directly to the flight deck: one in the forward and one in the rear cargo hold. The smoke detector in the toilet (located behind the F/Os side of the flight deck and directly in front of the forward cargo hold) will not trigger an alert in the flight deck as such, but its siren intended to call the flight attendants can certainly be heard in the cockpit as well.

Smoke in the cabin or the galley on the other hand is supposed to be detected and acted upon by the flight attendants.

Smoke in the lavatory or the cabin would typically be reported to the flight deck via an emergency call - but answering this will typically be lower on the priority list than establishing the aircraft in a climb, retracting the gear and so on.

A cargo smoke warning will trigger the master warning, a triple chime, the red "Check fire detect" warning light (mid-left on the lowest line of the CWP) and several lights on the upper right part of the overhead panel (in a slightly "sunk" section to the right of the T handles). The extinguishing agent will normally be released automatically in two steps; only correct operation of the system will need to be checked. This has definitely been trained in the simulator and should not cause a well-proven crew to shoot from the hip either.

Another possibility, of course, is smoke in the flight deck coming from whatever source. Air conditioning has been known to be a provider sometimes, but more often at low than at high power settings (with the HP taps open instead of the LP ones). But then again, training would have suggested putting on the masks and smoke goggles and entering one of the checklists offered for this situation.

I for one do not know and dare not suggest what may have happened here - the investigation will soon show.

Emerald Airways (HS748 Turbo Prop - 30 Mar 98) did something similar.

https://assets.digital.cabinet-offic...001_G-OJEM.pdf

I agree the elephant in the room will be exactly what prompted the decision to abort.

The decision must have been virtually simultaneously with the movement of the gear lever to UP (absent the scenario F16guy mentions) - to produce the visible damage to the aircraft on the ground. Nose gear doors open and crushed, main gear fully retracted and doors closed.

Ground contact must have occurred within a second or so of this moment in the gear retraction sequence:

http://airlinersgallery.smugmug.com/...%2846%29-M.jpg

...a very narrow window, where the long main gear have reached a point higher than the aircraft belly, but the nose gear and doors are still exposed. The undamaged main gear then completed the retraction cycle as the aircraft slid along the pavement.

Pattern_is_full - this sounds plausible.

http://www.aerotelegraph.com/wp-cont...n_luxair_2.jpg

Looking at the propellers, it seems that the #1 side has hit the ground: the blade tips appear missing at least on the blade that is visible. With the propellers running clockwise (when observed from behind), chances are that debris did not impact the cabin but got thrown away to the sides. #2 seems to be intact, but the blade angle seems to be a fair bit lower than the start/feather position displayed after a normal shutdown; this might hint at a quick shutdown via the T-handles.

Just a thought, I'm not familiar with Bombardier, but on some other aircraft an emergency call from the cabin will trigger the master caution. Unrelated to this incident, generally speaking, I think that's a good idea, it provides a hint that it's not a good practice to give priority to retracting the gear rather than answering an emergency call.

On the DH8-400, the emergency call will only trigger a chime and a yellow flashing light on the rear part of the radio control unit located at the rear end of the center console (IIRC, the -300 had no chime but the light in a more prominent position in the forward center part of the center console). One has to look at the panel to see the nature of the call.

I would be of the opinion though that flying the aircraft comes first: there are very few instances in which postponing the gear retraction, which takes mere seconds and brings the aircraft in a state covered by performance calculations, in order to take a call from the cabin is justified. If required, a relanding via a traffic pattern is usually a matter of a few minutes and initiating this maneuver 3 or 4 seconds later, but with a cleaned-up aircraft, will do more good than allowing one to get kicked out of the flow and possibly forgetting the landing gear retraction over the information received.