MSPeconomist

How about deferred maintenance on the toilet? How long can a SkyWest CRJ-900 fly around with only one operable toilet? I'm asking because I recently had the misfortune on one that generally looked old, battered, and dirty, with the FC lavatory taped closed in a way and with a sign that looked pretty permanent.

ATOBTTR

Last week I flew out of ATL on an MD-90. Pilot came on and told us the APU had an issue and we'd be starting the engines at the gate BEFORE pushing back, using ground power to start the engines. I was really hoping for a power-push but no luck.

jrl767

the MEL is standard throughout the industry: the airframe manufacturer (e.g., Boeing) uses a lot of safety and reliability and redundancy engineering such as Failure Modes and Effects Analysis and Failure Modes, Effects, and Criticality Analysis (FMEA/FMECA) to develop the list, and the certification body (e.g., FAA) approves it

it's been a long time since I worked in Boeing Commercial, but I seem to remember there are MEL permutations ... one that comes to mind is that some items of equipment are required to be operable in order to dispatch the flight, but an en route failure doesn't necessarily require the crew to divert; another is an ETOPS flight plan restriction (typically 180 minutes flying time to an alternate airport; with identified degraded system configurations, it's more like 90 or 120 minutes)

davetravels

WOW! I thought, maybe you stayed at a Holiday Inn Express last nite!!!

jrl767

it's been a long time since I stayed at a HIE too ...

appleguru

I flew on a CRJ last year that had a PACK deferred.. The second unit failed in flight, cabin depressurized at 33k feet and we had to make an emergency landing...

[edit] adding photo....[/edit]

MSPeconomist

That CRJ-200 looks surprisingly fresh and clean. I always get the tired, worn, and filthy ones.

EditingFX

Secure mask, THEN selfie. Well done.

edit: your seat mate looks to be questioning your framing.

baccarat0809

And to think, you were having such a good hair day before you had to put that rubber band on over your head.

Down3Green

The format of any MEL consists of a list of items organized by various aircraft systems (air conditioning, electrical, navigation, etc.). For a given item, it will then list Remarks/Exceptions and any performance penalties to be applied. The Remarks section will spell out any additional actions required in the case of deferral. Every 2 engine jet that I've flown has had a requirement that if one of the packs is deferred (it's called "Maintenance Carry Over" or MCO at Delta) then the plane must fly at FL250 or below. So, while I have no doubt that you had a rough experience on that flight, if the one pack was legally deferred prior to dispatch, you weren't at FL330 when the other one went down. You were somewhere below FL250 and that's a big difference when you're talking depressurization problems

appleguru

Interesting. You're the expert, just going based on what we were told after we landed.

Was this flight:

http://www.avherald.com/h?article=4835306c&opt=0

http://flightaware.com/live/flight/A...730Z/KGRK/KATL

Accoring to that, we were filed to fly at FL350, made it to 29,000 ft before we lost pressure and initiated an emergency descent to 10,000

Down3Green

Each item on the MEL in FAA 121 ops will also be designated with a "Repair Category" which delineates when the repairs must be made. The options are Category A, B, C, or D. While I can't say for sure what's in the MEL for a SkyWest CR9, most of the Lavatory systems that I've seen are Category C which are 10 days, not including the actual day of deferral. It's worth noting that Category B and C items can be extended on a one time basis with FAA notification. With that said, you would generally expect a Lav system to be fixed well before the full Repair interval. In fact, if you start to see a flight plan or logbook full of deferred items running right to their Category limits, that's a good sign of an overloaded MX system

Down3Green

appleguru,

The following is some text from what is called the MMEL or Master MEL for the CRJ which I found online. The MMEL is kind of a generic MEL established by the manufacturer and then refined by individual airlines. The quoted text are the Remarks for deferring a pack (note, there are (O) remarks and (M) remarks. The (O) refers to actions that the pilots must take while the (M) remarks are for mechanics)

As I said, the requirement of FL250 and below for single pack operation is pretty standard as far as I know. I do have to note that the MEL only applies to items that are discovered prior to dispatch. If a crew got airborne with 2 working packs and then one failed, they would handle that under the QRH, not the MEL. In that case, the QRH may authorize operations at a normal cruise altitude because you would have taken off with fuel that may not allow ops at FL250 which would require a higher fuel burn. In this case as a Captain, I would definitely get on the radio with the Dispatcher and Maintenance and discuss the best options.

So, in your case, the crew may have legally gotten airborne with 2 packs and had them fail individually in flight. If one really was deferred and the other failed while climbing into the 30s, that would be a no-no

HDQDD

APUs fail regularly. It's not a huge deal, because they're usually shutdown after electric/hydraulics are shifted to the engines anyway (i.e. before the flight takes off). The MD-90, and almost all jets*, require an air cart (or rampers call the "huffer" (sp?) cart) to inject air into the engine to turn the turbine before they can start it. This is the loud noise you'll hear hear outside as it forces air into the plane. Usually the APU provides this. One can also "cross bleed" air from one engine to another for starting purposes, although many airports don't allow this around the terminals because it produces a lot more thrust than idle. The ground power just powers the electrical onboard the aircraft. Airplanes also have batteries for this, but when ground power is available they'll almost always use it (unless parked remotely where it isn't available).

When I worked on the ramp many moons ago, it was rare to have a whole day without having to use the huffer cart at least once for an INOP APU aircraft (especially the darn CRJs).

*One exception to this rule I know of is the illustrious BAe-146 which can be electrically started.

HDQDD

Well, that sounds interesting. Hope they threw some miles at you.