DC-9 ground collision injures 6

[ORAC]

MINNEAPOLIS (AP) - A Northwest Airlines DC-9 that had reported hydraulic problems collided with another aircraft Tuesday on the ground at Minneapolis-St. Paul International Airport, injuring six people, officials said.

The six were taken to the hospital, but the extent of their injuries was not immediately known, said Pat Hogan, spokesman for the Metropolitan Airports Commission.

Northwest released a statement saying several crew members were injured, but that no passengers were hurt.

Hogan said the DC-9 had flown in from Columbus, Ohio, and landed without incident when the pilot apparently lost control of the steering on the way to the gate. The plane collided with a Northwest Airbus backing away from another gate for takeoff.

Passengers on both planes were evacuated, Hogan said.

After the crash, the DC-9 appeared to be partially lodged underneath the Airbus. The top of the DC-9's cockpit area had clipped the Airbus' wing and was damaged.

Hogan said the National Transportation Safety Board was investigating.

http://www.kare11.com/assetpool/images/05510213928_Northwest-collide.jpg

[readywhenreaching]

Facts from www.jacdec.de:

DATE: 10.05.2005
LOCAL TIME: 19:33
LOCATION: Minneapolis-Intl AP / MN (KMSP)_
COUNTRY: USA

AIRLINE1: Northwest AL
TYPE1: Douglas DC-9-51
REGISTRATION1: N763NC
C/N1: 47716
AGE1: 28 y + 11 m
OPERATION1: DSP
FLIGHT No.1: NW 1495
FROM1: Columbus
TO1: Minneapolis
VIA1: -
OCCUPANTS1:
PAX: 93
CREW: 5
FATALITIES1:
PAX: 0
CREW: 0
OTHER: 0
INJURIES1:
PAX: 0
CREW: 6
OTHER: 0
DAMAGE TO AIRCRAFT1: substantial / DBR

AIRLINE2: Northwest AL
TYPE2: Airbus A319-114
REGISTRATION2: N368NB
C/N2: 2039
AGE2: 1 y + 7 m
OPERATION2: DSP
FLIGHT No2: NW 1849
FROM2: Minneapolis
TO2: San Antonio
VIA2:_-
OCCUPANTS2:_
PAX: -
CREW: -
FATALITIES2:_
PAX: 0
CREW: 0
OTHER: 0
INJURIES2:_
PAX: _0
CREW: 0
OTHER: 0
DAMAGE TO AIRCRAFT2:_minor_

When the DC-9 taxied to its assigned gate, it was hit by the Airbus near the 'G' concourse causing substantial damage to both aircraft. The Airbus was pushing back from its gate C12 at the time. Its right wing struck the upper cockpit area of the DC-9 which became buried underneath. At least 6 crew members on board the DC-9 were injured, one of them serious.
NOTE: On 3rd Dec.1990 two other NWA aircraft (DC-9 + B727) collided in foggy conditions on the runway at Detroit-Metro causing 8 fatalities.

[bafanguy]

The DC9 lost control of its steering...? That's hard to believe. Both versions of the event mention the Airbus pushing back at the time. Lacking more info, the pushback seems to be the key.

[barit1]

The original news story I heard mumbled something about a steering problem with the DC-9. Now that seems apocryphal.

I was in ATL about 1984 when two EAL DC-9's were both powering back from opposite gates on two concourses, and tangled tailfeathers as they backed into each other. Not pretty.

[nwaflygirl]

The DC-9 lost it's hydraulics. Both aircraft were evacuated.

[broadreach]

Assume/hope both flight deck crewmembers were heads up when the crunch came and that they've not had unwanted haircuts. And that whatever injuries may have occurred are more to the psyche than to physic.

That said, it certainly does look expensive.

[Ignition Override]

The DC-9 reportedly already had a problem with either hydraulic pressure or quantity, maybe both. Don't remember if it was the left or the right system. Both systems connect to both braking systems. They tell me that the right engine pump is backed up by an aux. electric pump (3,000 psi, via left gen. bus). The left engine pump is backed up by the alternate pump (1800-2500 psi. via right dc bus), but powered by fluid pressure in right system via "motor/pump" action. Accumulators should give 3-5 brake applications.

The parking brakes supposedly need at least 1400 psi from either system to work. A very rare anti-skid electric (ground shift) failure could cause total braking failure below about 20 knots if switch in armed position on -30 series. Or so they told me.

NWAFlyGirl-I'm not quite sure about any of this system info., but can your flightcrew correct me on some of it? I only learned about this from neighbors on an overnight .:confused: The planes I fly have Pratt & Whitneys with 'autofeather' capability :8 .

[SPFlyer]

see picture......

http://www.airdisaster.com/news/0505/11/news.shtml

[apaddyinuk]

Let that be a lesson to any pax and crew who insist on unbuckling their seatbelts as soon as the plane decelerates on the runway!

[Shore Guy]

Bad couple of days for NWA at MSP.....


'Inches from disaster'

Life working around large aircraft can be very dangerous. But fuel truck driver Bruce Burns never imagined being involved in, and better yet, surviving an accident with a plane.

"I am just surprised I am standing here right now," said Burns, who talked exclusively to 5 EYEWITNESS NEWS.

Bruce Burns was driving a truck filled with fuel at Minneapolis/St. Paul International Airport when he said he blacked out and slammed right into a DC-9 parked at the airport. The pictures are incredible; the fact that there wasn't an explosion is a near miracle.

"There is 2,000 gallons of fuel and 1,000 gallons of jet fuel in there. If it exploded, the aircraft, the truck would have been gone. And I wouldn't be sitting here right now. There was potential for disaster."

Burns said he was ending a 16-hour day when the crash happened. The violent collision pushed the plane—which weighs 57,000 pounds empty—10 feet sideways.

"I don't remember anything prior to the accident and I don't remember driving into the aircraft or anything like that," Burns said.

Airport police have been looking at tapes from surveillance cameras. They are trying to determine exactly what happened. In the meantime Burns realizes that in this world of huge planes and heavy trucks, he survived by the tiniest of margins.

"A few inches over, and I probably would have been killed." **********************************************



......Don't know how long this link will be alive...

http://www.kstp.com/article/stories/S8166.html?cat=1

[lomapaseo]

We may have here some confusion about the hydraulic systems in conjunction with a known malfunction unfortunately compounded by a discretionary engine shutdown during taxi causing further loss of hydraulics on the good system and then a reactionary selection of max reverse on the one running engine, but without the hydraulically operated reverser buckets, simply adds to the forward asymetrical motion.

So can there be there some discussion about this scenario?

[bafanguy]

loma,

Hadn't heard the part about the engine shutdown. That's a wrinkle I hadn't thought of. As for the reverser, each has its own accumulator which would have extended the buckets. However, the accumulator pressure for the reverser in the failed hyd system may have been depleted during landing rollout extend/stow operation.

I guess we don't know which hyd system originally failed ? For purposes of discussion only as all the facts aren't available, if the left system had failed originally and they shut down the right engine during taxi in, the right system would still have the electric aux pump to provide brake pressure through the right system.

We always shut down the right engine during taxi in so I'm assuming that if they also made a customary shut down, it would've been the right engine.

This is all a pretty interesting case.

[GlueBall]

And no available braking from the hydraulic brake accumulator?

[bafanguy]

glueball,

It all depends on the circumstances...and that's what we don't know: the circumstances.

What I can tell you from having a hydraulic failure or two in the DC9/MD80 is that, on landing rollout, any brake accumulator pressure from the failed system would be rapidly depleted during the landing roll.

On the DC9-30 where there is a brake selector that allows isolation of either brake hydraulic system, the failure procedure calls for putting the brake selector to the OPERATIVE system, thereby conserving the accumulator pressure in the failed system for later use, if needed ( reselection of the failed system would be required ).

The airplane in question is a DC9-51...not a -30. I don't know if the -50 series has the same brake selector as the earlier series ( the -80 series does not have this selector ), so it is hard to comment with any accuracy.

Perhaps someone with time in the -50 series can comment.

[saline]

Reports I have read indicate the DC-9 had considerable forward thrust which not only pushed it under the Airbus, but continued to move both airplanes forward a considerable distance. Reportedly this was because the captain was attempting to use reverse thrust to stop but instead got to almost takeoff power (on the running engine) without the buckets being deployed.

Cockpit crew had to be cut out due to buckling of fuselage near forward part not allowing doors or windows to open. Considerable fuel leaked from Airbus.

This seems to be even worse than the pictures indicate. Passengers indicated a reluctance on crew's part to evacuate even though much spilled fuel was evident.

Ugly.

[bafanguy]

saline,

Let's wait until there are some "official" reports of the details before we say what the captain did or did not do. You say, "...reports I have read...", but do not provide those reports or the authors of those reports.
Let's just wait a bit. No one profits by hanging the crew before the trial.

[Ignition Override]

Bafanguy-my sources tell me that yes, the -30, -40 and -50 all have the same brake selector, which is normally left in the "Both" position, allowing both hydraulic systems to supply all brake pressure needs. Only the -10s (now retired, and destroyed[?] :yuk: ) had a different yellow lever, also above the captain's radar altimeter and standby ADI, requiring pilots to select one hydraulic source at a time. On some -10s, personnel noticed that after many years, due to infrequent use of the lever, it needed to be alternated quite often-once during cruise. How good are the cables to the brake selectors in the -30, -40, and -50? Are they checked often?

Did the DC-9 in question have an inop. (MEL) thrust reverser for the operating engine? Even the DC-9 thrust reversers have a hydraulic accumulator, and a 'reverser accum low light' should indicate inadequate pressure, which can be recharged by a circuit breaker-at least this is what my sources tell me.

I wonder how often such systems are checked, with so much financial pressure to outsource airlines' major maintenance? This is only the beginning of a very unfortunate accelerating trend :ugh: :suspect: . Maybe this plane was at Dothan recently (...woops!...), or San Antonio? Maybe not. Nevertheless, only the supervisor at an outsourced facility must be FAA licensed-not the other workers, whether in the US or at the facility in El Salvador which overhauls about a fourth of JetBlues Airbus fleet-reportedly a rather complex aircraft.

[Halfnut]

Ignition Override,

I’ve flown the -10, -50 and currently fly the -80. Your source is correct on the brake system on those planes. I don’t have my manuals anymore for the -50 but I never remember moving the lever out of the both position but we didn’t single engine taxi either (the old days of cheap fuel.)

Yes you can dispatch with a thrust reverser inop but the hydraulic accumulator circuit breaker is pulled and collared. (I’m at home and don’t have access to a MEL) If I remember correctly that circuit breaker is behind the Captains left shoulder. Not an easy maneuver in the heat of battle when you’ve lost all your brakes. To expect the Captain to loosen his straps, spin around in his seat, find the circuit breaker in a sea of C/Bs, yank off the collar, push back in the circuit breaker, spin back around in his seat and then deploy the marginally effective thrust reverser. Even at full reverse the thrust reversers on the -50 are more of a noisemaker than anything else. They are more effective at high speeds (not much) then low speeds.

This accident bothers me because the DC-9 brake system is very straightforward with two completely independent systems. At my carrier we had a string of transfer pumps crack on several aircraft leading to a complete loss of hydraulic quantity on each system. We have replaced all the transfer pumps with a more “robust” pump. Since then we have not had any more problems.

Even if NWA had a cracked transfer pump the crew would have lost steering that would force them to set the brakes and call for a tug. If it is not a cracked transfer pump then crew should have had at least one brake system powered by one of four pumps delivering 3000 psi hydraulic pressure. With a dual flame out and no APU they should have had two accumulators good for 5 brake applications before depleting the accumulators.

I understand the Captain is in serious condition with head wounds and fuel burns, while the first officer was also hurt, but not as badly. On the ground, one mechanic apparently received chemical burns, and a ramp agent who ran over to assist was overcome with jet fuel that sprayed into his eyes.

[bafanguy]

halfnut,

I'm interested in your comments about the cracked transfer pumps. I've never heard of this problem ( not that I've heard of EVERYTHING by a long shot ).

How long ago did this happen at your carrier ? And, when you say it caused a loss of fluid in "each" system, I take it you mean BOTH hyd systems ? Did this happen in flight ?

As you mentioned, the -9 has some of the best systems design when it comes to dealing with abnormal conditions. Simple is better any day.

[saline]

saline,

Let's wait until there are some "official" reports of the details before we say what the captain did or did not do. You say, "...reports I have read...", but do not provide those reports or the authors of those reports.
Let's just wait a bit. No one profits by hanging the crew before the trial.

Sorry, thought this was the "roumours" & news section. The "report" was forwarded by someone on the scene (who is in no position to be identified as a spokesman of any kind) and was early speculation based on comments and cursory evidence. Again, still a "rumour".

Maybe we need to drop these threads and wait for the NTSB report, eh?

[Ignition Override]

Halfnut: The transfer pump you refer to must be the alternate pump. My"source" claims that it is the only connection between the two systems and that the left can operate, via the gear sump fluid (but with no right pressure indicated) the landing gear, right half of the nosewheel steering. From the right to the left, the left at reduced pressure (18--2400 psi), if the normal fluid in the right side is available over 2,000 psi., to go through priority valve (normally 1500 in cruise or 3,000 during approach, taxiing and until Climb Checklist, following "uplatch check"), to get to the non-priority items. A problem with whichever DC bus (rare) might affect the anti-skid, if left on after landing and the right DC Bus powers the alternate hydr. pump. Doubt that they also had such an electrical abnormal, or had a groundshift failure. The Aux pump powered by Left Gen. Bus, based on my information. Better go now. Don't want to look too sleepy in Sun. School. :hmm: ...eing'schlohfe...

[Halfnut]

Gosh Ignition Override I didn’t know I was going to get an oral on the DC-9 hydraulic system. Yes your source is correct on the exact numbers and wiring on the DC-9. The Transfer Pump will transfer pressure but not liquid. Depending on which side has more pressure will make one side a motor and the other side the pump there by pressurizing the other side. It does it in pulses and if you sit over the wing on the ground with one side unpressurized you can hear the Transfer pump making a thumping noise under your feet. But getting down to the brass tacks it is enough power to keep your brake system charged so you can stop the aircraft.

I’ve been told too that the Transfer Pump is the only place where the two systems come together. Ask your “source” if there are any hydraulic fuses or check valves on the brake accumulators to maintain brake pressure in the event of a complete loss of hydraulic fluid on either side?

[Ignition Override]

Halfnut: my source has no idea about the fuses etc .:)

[Few Cloudy]

- The transfer pump has had various names (Power Transfer Unit - Alternate Pump etc.) on various DC 9 / MD models. There have certainly been cases of case cracking with this unit, which can lead to loss of fluid. Once one side is fluid free and thus free rotating the other side soaks up pressure from the live system in the attempt to maintain pressure on the dead side. This results in an almost total hydraulic failure. The problem was known over seven years back and certainly occured in an airline I worked for.

- This engine shut down business - I once worked out how little fuel you saved - especially considering increased thrust on the live engine when making turns towards it. Maybe someone will re-consider whether making it an SOP is such a bright idea - especially when the Pratt should be given a cool down period after landing.

Add some system failure - electrical or hydraulic and you could be compounding the problem.

FC.

[bafanguy]

Few,

Perhaps what you describe explains the feature of the MD80 that automatically closes two shutoff valves if either reservoir fluid level drops below "...a safe level..." ( actual quantity unspecificed in our manual ), rendering the transfer pump inop.

I flew the -30 for a very long time and was never told of the condition you describe with the alt pump in a fluid loss condition. But that's what keeps it so interesting...learn something new all the time.

The Douglas DC9 manual contains the following statement re the alt pump: "The input pressure from either left or right hydraulic system is controlled so that not more than 2 gallons per minute flow will be used to drive the hydraulic motor/pump." Further, the DAC manual says that the engine driven and aux electric pumps are capable of 8 gpm @ 3000psi.

Perhaps this feature malfunctioned in the cases you experienced. At any rate, always fun to have some "shoptalk" with fellow DC9 pilots.

[Few Cloudy]

Bafanguy,

It´s been a while but MDC had the pump casing modified as I recall.

The condition didn´t occur with a straight loss of fluid but only when there was a crack in the casing of the pump. (Of course the pump normally won´t run unless there is a pressure drop on on side and a crack in the casing tended to create a very sudden loss.) Could well be that the system on the good side recovers when the cut off level is reached- but the incident may have happened by then.

A similar pump was used by the way on the DC-10 between the systems, where it was called the motor pump - typical Douglas - a new name for an old system every model.

I once had access to all the literature on this but am working from memory now.

All the best,

FC.

[320DRIVER]

Picture here...

Picture (http://www.airliners.net/open.file?id=841968&size=L&width=1024&height=693&sok=&photo_nr=)

[bafanguy]

Apparently, there's no official details out yet as no one is talking about this one lately.

[broadreach]

It'd be very interesting to learn how the two aircraft were extricated from this embrace, the DC-9's port wing and fuselage under and lifting the 320's fuselage. It must have been a very delicate operation, not to compound the damage; where do you put any airbags under the 320 if the DC-9's wing is nearly up against the 320's main gear? You can't pull the DC-9 out then, can you. Lift the 320's wing between root and stbd gear? Gosh, with people watching from the balcony, a job to get done very quickly. Also interesting, somewhere down the road, to learn whether either aircraft get back into service, how long it takes. The 9 might just be scrapped but the 320?

My apologies to the DC-9 captain for a flippant post earlier on re haircuts. Obviously a lot more potential for damage inside than I'd originally realised from the first photos posted. I do hope it's not too much more than a dust yourself off thing.