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IFlyVeryLittle
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Crippled by a windshield wiper

Sun Apr 11, 2021 5:21 pm

Never had a flight cancelled over a windshield wiper, but Saturday it happened. And it raised a question. As we taxied out at a rainy Atlanta, the three-month old A321 stopped short of the runway for something like 10 minutes before a crewmember said they were having trouble shutting off the windshield wipers. She mentioned a speed limit for activated wipers and said we were no go if they couldn't shut them off. A bit later, still short of the runway, she said the crew cycled the breaker and still the wiper couldnt be commanded to shut off. So, back to the gate and the passengers were deplaned. With no replacement panel to be found, the tech team sought to replace the switch. Most passengers rebooked and the flight eventually left hours later, but I was left wondering: why would they have try to shut off the wipers before even taking the runway? And had they not discovered they couldn't shut them off once airborne, would that have required a return?
 
Bellerophon
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Re: Crippled by a windshield wiper

Sun Apr 11, 2021 6:19 pm

I think the most likely concern would be that with the wipers still cycling above their limiting airspeed they could break off and cause damage, possibly by being ingested into an engine.

I would be more concerned that they couldn't shut the wiper down by pulling its breaker!
 
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fr8mech
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Re: Crippled by a windshield wiper

Sun Apr 11, 2021 6:29 pm

Bellerophon wrote:
I would be more concerned that they couldn't shut the wiper down by pulling its breaker!


Pulling the breaker will stop the wiper. They were trying to get the wiper system to operate normally by cycling the breaker. Cycling the breaker is a normal troubleshooting technique used to ‘reset’ components/systems.

The OP did mention that the crew ‘cycled the breaker’.

Whether an aircraft would return or not, I think, would be up to the captain.

I’ve had plenty of aircraft return to the ramp, after block-out, with wipers that wouldn’t park. It seems to me that everyone goes for the switch, but, anecdotally, I say it’s the converter/motor.
When seconds count, the police are minutes away, or may not come at all.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
CosmicCruiser
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Re: Crippled by a windshield wiper

Sun Apr 11, 2021 7:07 pm

There's also the issue of leaving with a known problem.
 
e38
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Re: Crippled by a windshield wiper

Sun Apr 11, 2021 11:40 pm

IFlyVeryLittle wrote:
why would they have try to shut off the wipers before even taking the runway? And had they not discovered they couldn't shut them off once airborne, would that have required a return?


When operating, the windshield wipers on the A320 series aircraft tend to be very noisy; sometimes it can be quite distracting. It is very common during taxi operations that if the aircraft stops--either told to hold position by ground control or if reaching the queue of aircraft at the end of the runway--to turn the windshield wipers off. The general philosophy is that while on the ground, if not needed, turn them off. It is my guess that in the situation you described, it was at this point the crew discovered they would not shut off.

Regarding your question, "would that have required a return?"

The windshield wipers have an operating airspeed limit of 230 KIAS. It may be possible to continue, but would require coordination with air traffic control regarding the reduced airspeed, plus; fuel burn figures would need to be recalculated for the duration of the flight. In general, a return to the departure airport would probably be the most logical decision. Obviously, this situation would not warrant an overweight landing--you would burn down fuel, if applicable, until reaching landing weight. This would be coordinated between the captain, flight control (dispatch), and probably maintenance control as well.

Note comment above by CosmicCruiser: yes, once the discrepancy was discovered, you would not continue without having maintenance address the issue.

e38
 
Bellerophon
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 1:12 am

fr8mech

... Pulling the breaker will stop the wiper. ...

If pulling the breaker did stop the wipers, then I have obviously misunderstood the OP's post to mean that the crew were unable to stop the wipers by any means.

I have no knowledge of Airbus or FAA requirements - and I intend no criticism of the crew - but assuming that no other circuits were controlled by that breaker, would the crew not have been allowed to continued with the breaker pulled, resetting it for landing if the wipers were required?

I've been retired a few years now, but unless UK CAA procedures have changed, then having departed the ramp and provided the wipers could be stopped by pulling the breaker, I think it would have been at my discretion to continue the flight.


... I’ve had plenty of aircraft return to the ramp, after block-out, with wipers that wouldn’t park ...

On one aircraft I flew, wipers not parking correctly was a rare problem but with an unfortunate consequence. On taxi out it would prohibit take-off or after take-off it would require a return, so we never used wipers on the ground or during take-off, only for approach and landing.

Best Regards

Bellerophon
 
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Starlionblue
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 1:39 am

The issue apparently came up after dispatch. The MEL doesn't need to be applied, but it can provide useful guidance.

I don't have an A320 MEL, but the A330 should be fairly similar in this respect. It says that if one or both wipers are continuously running, the aircraft can dispatch with the wiper(s) deactivated, provided the aircraft is not operated in precipitation within the terminal areas. Approach minima should also not require the use of wipers.

As Bellerophon says, commander's discretion after dispatch. As long as the wipers can be parked and there isn't pouring rain at departure or destination, I suppose you can continue. If there is a lot of rain, you really want to see where you are going. :)
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
GalaxyFlyer
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 2:06 am

I’ve only flown two planes with wipers and nearly useless on both. The B727 wipers made a racket and, like those on the C-5, didn’t seem to be much good at clearing the rain. The A-10 had a flat center pane whic was prett opaque in rain especially after using the gun. The bizjets (6 ratings) didn’t have wipers, the techs kept the windows clean and polished with RainX. This seemed, at least, as good and didn’t cause mechanicals.
 
MSJYOP28Apilot
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 2:52 am

Starlionblue wrote:
The issue apparently came up after dispatch. The MEL doesn't need to be applied, but it can provide useful guidance.

I don't have an A320 MEL, but the A330 should be fairly similar in this respect. It says that if one or both wipers are continuously running, the aircraft can dispatch with the wiper(s) deactivated, provided the aircraft is not operated in precipitation within the terminal areas. Approach minima should also not require the use of wipers.

As Bellerophon says, commander's discretion after dispatch. As long as the wipers can be parked and there isn't pouring rain at departure or destination, I suppose you can continue. If there is a lot of rain, you really want to see where you are going. :)


Actually, most US based airlines are required to MEL placard maintenance items after gate push but before takeoff. OP mentioned that is was rainy at his departure point ATL. What typically happens is cockpit crew calls maintenance and tries a reset if one is available. If reset does not work then the MEL is applied if it is abled to be crew placarded. If not able to be crew placarded or the MEL is not legal to accept then aircraft has to return to the gate for repairs or maintenance placarding.

In this case it appeared that with the rain and failed reset, the MEL was not legal to apply so it needed to return to the gate.
 
Woodreau
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 3:08 am

The MEL will state whether an item may be deferred by the crew instead of maintenance.

If it is crew deferrable there will be a maintenance procedure that will be outlined for the crew to perform. After the procedure is complete the PIC still needs to coordinate with maintenance and complete the paperwork. Then needs to get with dispatch to get an amendment to the flight release.

If the crew elects not to do a crew deferral then it needs to return to the gate to allow maintenance to complete the deferral if the item is deferrable at all.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
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glen
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 9:56 am

Whenever you stop the wipers via the wiper switch they continue to move into the park position. When you shut them off by pulling the C/B they will probably stop at whatever intermediate position they are, as you just interrupt the power. Although the speed limit is described as maximum "operating" speed, I would certainly apply it when they are not in the parked position, even if not moving. So returning to the gate seems a very reasonable decision to me, if you can't stop them via the standard switch.
"The horizon of many people is a circle with zero radius which they call their point of view." - Albert Einstein
 
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fr8mech
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 10:46 am

Bellerophon wrote:
I have no knowledge of Airbus or FAA requirements - and I intend no criticism of the crew - but assuming that no other circuits were controlled by that breaker, would the crew not have been allowed to continued with the breaker pulled, resetting it for landing if the wipers were required?


That really depends on how the MEL is written, what the DMP says, and what the operator’s approved procedures are. I’ll dare say, that 20’ish years ago, depending on the crew, that aircraft would have gone...had we been operating it. Today? Back to the ramp to get addressed by maintenance. The active rain also make it an issue. I don’t recall any aircraft that would have been allowed to depart with an inoperative windshield wiper system when the was precipitation in the area.
When seconds count, the police are minutes away, or may not come at all.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
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T18
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 1:56 pm

fr8mech wrote:
Bellerophon wrote:
I have no knowledge of Airbus or FAA requirements - and I intend no criticism of the crew - but assuming that no other circuits were controlled by that breaker, would the crew not have been allowed to continued with the breaker pulled, resetting it for landing if the wipers were required?


The active rain also make it an issue. I don’t recall any aircraft that would have been allowed to depart with an inoperative windshield wiper system when the was precipitation in the area.


MEL book I have for the CRJ7 allows it, oddly if the affected side is parked we have no limits only if it is not parked does it give a 250 knot restriction. I've always found it kinda odd that there are no inherent restrictions.
“Racing's important to men who do it well. When you're racing, it's life. Anything that happens before or after is just waiting.” ― Steve McQueen (Le Mans) 1971
 
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fr8mech
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 2:17 pm

Quick question for all you pilots out there: do you actually use the damn things? I’ve ridden jumpseat countless times, and the only time I’ve seen them in actual use was sitting at the end of the runway for takeoff, and the crew activates them for a few seconds so they can have a “clear” view of the runway. Never seen them used in flight.
When seconds count, the police are minutes away, or may not come at all.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
GalaxyFlyer
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 2:20 pm

Not much in my experience
 
CosmicCruiser
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 2:37 pm

No reason to use them in flight except for landing and then only in heavier rains.
 
Lpbri
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 4:36 pm

I checked an MEL for an A320 wiper. A bit complex, but it says this: If the rain repellant system is operative, there are no MEL restrictions. I believe most carriers may have deactivated their systems, dunno. Otherwise, no rain known within a 5 mile radius of the departure or arrival airports. Approach minima does not require their use. Auto land may be downgraded. Kind of odd because the only way to know if they are inop is it’s raining in the first place.
 
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Web500sjc
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 8:09 pm

Lpbri wrote:
I checked an MEL for an A320 wiper. A bit complex, but it says this: If the rain repellant system is operative, there are no MEL restrictions. I believe most carriers may have deactivated their systems, dunno. Otherwise, no rain known within a 5 mile radius of the departure or arrival airports. Approach minima does not require their use. Auto land may be downgraded. Kind of odd because the only way to know if they are inop is it’s raining in the first place.



MEL outlines procedures for dealing with issues known before takeoff. So if the wiper is MELd, the above MEL doesn’t allow the airplane to operate to an airport with rain around it. Obviously, if you don’t know about the wiper issue before takeoff, then You would use the In flight checklist to deal with the issue.
 
RetiredWeasel
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 8:14 pm

Jumpseating on a Continental Air Micronesia 727 flight before push back, I observed the CPT opening up the side window and reaching around and applying Rain-X to his front window. I asked him how it worked, and he stated during the rain showers when landing at the airfields in the islands, it did the job better than the wipers. Honestly don't know what the FAA would think.
 
Okie
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 9:11 pm

RetiredWeasel wrote:
Jumpseating on a Continental Air Micronesia 727 flight before push back, I observed the CPT opening up the side window and reaching around and applying Rain-X to his front window. I asked him how it worked, and he stated during the rain showers when landing at the airfields in the islands, it did the job better than the wipers. Honestly don't know what the FAA would think.


Boeing thought "RainBoe"
Unfortunately the aerosol was an environmental hazard and had canister leaks in the cockpit that caused pilot issues.

Like many things in the past "an excellent performer but a bad actor"

Okie
 
CosmicCruiser
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Re: Crippled by a windshield wiper

Mon Apr 12, 2021 11:40 pm

Okie wrote:
RetiredWeasel wrote:
Jumpseating on a Continental Air Micronesia 727 flight before push back, I observed the CPT opening up the side window and reaching around and applying Rain-X to his front window. I asked him how it worked, and he stated during the rain showers when landing at the airfields in the islands, it did the job better than the wipers. Honestly don't know what the FAA would think.


Boeing thought "RainBoe"
Unfortunately the aerosol was an environmental hazard and had canister leaks in the cockpit that caused pilot issues.

Like many things in the past "an excellent performer but a bad actor"

Okie


We had the RainBoe disabled in our 727s.
 
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Starlionblue
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Re: Crippled by a windshield wiper

Tue Apr 13, 2021 2:13 am

fr8mech wrote:
Quick question for all you pilots out there: do you actually use the damn things? I’ve ridden jumpseat countless times, and the only time I’ve seen them in actual use was sitting at the end of the runway for takeoff, and the crew activates them for a few seconds so they can have a “clear” view of the runway. Never seen them used in flight.


Yes, we do. Many of our ports are regularly pounded by tropical rainstorms.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
r6russian
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Re: Crippled by a windshield wiper

Tue Apr 13, 2021 6:39 am

Surprized waxing windshields isnt a common thing in aviation. I wax my windows in my cars and by 30mph all the rain blows right off. The heavier it rains the better it clears. Just a single layer of generic automotive wax lasts 3-6 months and unlike rainx, isnt defeated by a single wiper wipe. And now new ceramic coatings last multiple years to where you just hose your car off and its back to fresh detailed pristine, those bead water off even better and are impervious to wiper usage. In reality, you dont use the wipers at all after wax/ceramic. Ive gotten 8years from a set of wiper blades 2 sets in a row now, probably run the wipers literally 30-50 wipes a year.
 
acmx
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Re: Crippled by a windshield wiper

Tue Apr 13, 2021 2:04 pm

Where I work (US based) a known issue between block out and take off would have to be addressed before flying. I think that’s pretty common here but don’t really know.

Opening a breaker to deactivate a circuit then flying would have to be backed up by some approved document, most likely the MEL but maybe the QRH or something. If The MEL is approved for crew deferral then they follow the procedure and continue on, if not it comes back for mx to deal with. Pulling the breaker and seeing the wiper stop isn’t good enough to continue, you have to have something saying it’s safe for flight with that circuit deactivated. That breaker, while unlikely in this case, might supply power to other things.

One of the things I like about the bus (a300) I work on is that lots of MEL’s just have you place the switch in the off position and placard. No breakers to pull or deactivation procedures to follow. I haven’t looked into it, but if that’s the case with the wiper system then it wouldn’t offer any relief in this situation.
 
GalaxyFlyer
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Re: Crippled by a windshield wiper

Tue Apr 13, 2021 3:16 pm

r6russian wrote:
Surprized waxing windshields isnt a common thing in aviation. I wax my windows in my cars and by 30mph all the rain blows right off. The heavier it rains the better it clears. Just a single layer of generic automotive wax lasts 3-6 months and unlike rainx, isnt defeated by a single wiper wipe. And now new ceramic coatings last multiple years to where you just hose your car off and its back to fresh detailed pristine, those bead water off even better and are impervious to wiper usage. In reality, you dont use the wipers at all after wax/ceramic. Ive gotten 8years from a set of wiper blades 2 sets in a row now, probably run the wipers literally 30-50 wipes a year.


Small problem of heated windscreens, the wax would melt, then erode off in the wind or rain blast.
 
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dennypayne
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Re: Crippled by a windshield wiper

Tue Apr 13, 2021 3:46 pm

GalaxyFlyer wrote:
r6russian wrote:
Surprized waxing windshields isnt a common thing in aviation. I wax my windows in my cars and by 30mph all the rain blows right off. The heavier it rains the better it clears. Just a single layer of generic automotive wax lasts 3-6 months and unlike rainx, isnt defeated by a single wiper wipe. And now new ceramic coatings last multiple years to where you just hose your car off and its back to fresh detailed pristine, those bead water off even better and are impervious to wiper usage. In reality, you dont use the wipers at all after wax/ceramic. Ive gotten 8years from a set of wiper blades 2 sets in a row now, probably run the wipers literally 30-50 wipes a year.


Small problem of heated windscreens, the wax would melt, then erode off in the wind or rain blast.
I was gonna say, 500mph vs 70mph probably makes a big difference in this case. Although I do have the ceramic coating on my wheels and it is pretty magical.
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