donnf
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ATR 72 Apron Safety

Mon Apr 23, 2018 6:54 am

Re: ATR-74 aircraft operated by Mayanmar International Airlines (MNA). I was a passenger on MNA flght 316 on 09 April 2018, travelling from Dawei to Yangon, Myanmar. The airport is small, and typically there are at most two aircraft loading at the same time. At the time of my flight here were two air craft on the apron area. One was a jet-engine type, the other was an ATR-74 that I was waiting to bord. Its nose was facing the terminal building.

Passengers were being guided along the length of the ATR aircraft on the starbord side and around the tail of the ATR to the aft-port door which is behind the port engine. As I emerged from the terminal building I heard the ATR engine noise. At first I could not tell which engine was making the noise, as the port engine was hidden from my view by the ATR fuselage; but the starbord prop was turning very slowly. I learned later that the starboard engine provides "hotel power" for the ATR.

Ground staff were directing the passengers to walk outside the starbord wing and towards the tail. At a point about 50 ft or so behind the tail, the engine noise (clearly from the port engine) became almost painful. Passengers with free hands used them cover their ears. And as the line of passengers made a U-turn and came closer to the portable metal steps at the aft door for boarding the ATR, the high velocity hot exhaust, and the noise, became almost incapacitating. There were several ground crew at the boarding steps with rain umbrellas that they were using to deflect --- unsuccessfully --- the airflow, heat, and exhaust gasses away from the boarding passengers.

I am certain that what I described above is a recipe for a serious problem, and is not a standard operating procedure.

Do any of you have data about the recommended safe distances from the exhaust of the ATR-74.

donnf
Last edited by SQ22 on Wed Apr 25, 2018 5:10 am, edited 1 time in total.
Reason: Typo fixed
 
BlueberryWheats
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Re: ATR-74 Apron Safety

Mon Apr 23, 2018 7:45 am

I'm guessing you mean ATR-72? They don't have an APU but engine 2 can be used to provide ground power without spinning the prop (maybe you saw it windmilling).

So all was fine.
 
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SQ789
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Re: ATR-74 Apron Safety

Mon Apr 23, 2018 7:56 am

ATR 72 is the right one!
We are Freedom & Peace Sharing the passion for aviation
 
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airkas1
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Re: ATR-74 Apron Safety

Mon Apr 23, 2018 8:12 am

We always hook up a GPU to the aircraft, so the 'APU' in engine #2 is only operating while passengers are still/already inside. Either way, we always direct passengers alongside the port side of the aircraft. Either towards the nose and then to the walkways to the terminal. In high wind, sometimes we have to park the aircraft differently and passengers embark/disembark around the tail and then straight to the terminal. Always away from the 'APU'. But as I mentioned, it's usually off due to the GPU hooked up.

As for your post, I'm don't really see it as a 'serious problem'. But I do understand and agree that it's not ideal to have passengers walk near the 'APU' due to the exahust fumes and noise. And as an above poster mentioned, my guess as to why the prop was slowly turning would be windmilling as well. So all in all not really unsafe practices, but inconvenient ones.
 
donnf
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Re: ATR-74 Apron Safety

Mon Apr 23, 2018 12:40 pm

The key concern I had was the proximity of the loading steps to the exhaust port of the port-side engine. That engine was running while passengers were boarding about 30 ft behind the engine. I could feel the heat, and force of the exhaust, and the noise level was nearly painful. But my question was about the maufacturer's recommended safe clearances for personnel and passengers benind the port-side engine.
When it is operating. Does anyone know that piece of information? I have looked on line for it, it with no success.

Donnf
 
n757kw
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Re: ATR-74 Apron Safety

Mon Apr 23, 2018 1:32 pm

When I worked around the ATR-72-200, upon arrival on the ramp the No. 1 engine was shut down and the No. 2 engine went into hotel mode until ground power was hooked up. Then it was shut down. After passenger loading, the No. 2 engine was started in hotel mode. Ground power was removed and once clear of the aircraft the prop brake was released. The blade immediately spins up. No. 1 engine was usually started after leaving the ramp area at my carrier.

I never saw the No. 1 engine running during ground ops mainly because we had the forward cargo compartment forward of the No. 1 engine. I don't know if the No. 1 engine even has a prop lock. All the carriers I have flown the ATR on have all used ground power and boarded from the left side of the aircraft.

N757KW
"What we've got here, is failure to communicate." from Cool Hand Luke
 
VSMUT
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Re: ATR-74 Apron Safety

Mon Apr 23, 2018 7:22 pm

It sounds as if the scenario you described is the passengers walked along the right side of the aircraft, around the rear and onto the boarding steps on the rear left side of the aircraft, correct? The rear right door isnt for boarding passengers, its both too small and doesnt have any steps, and only the right engine can run in hotel mode. The left engine would have been windmilling at most, and any heat from it would be residual. If the left engine was really running, you wouldnt have noticed the heat from the massive blast of air from the propeller.
Having passengers on the right side is certainly unorthodox, especially with hotel mode running. Sounds weird.
 
donnf
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Re: ATR 72 Apron Safety

Thu Apr 26, 2018 8:23 am

Thanks for the feedback. Yes, loading was via the aft-rear door, after the passengers walked along the starbord side and around the tail. The noise, heat, and air blast that I and other passengers felt appeared to be coming from the port (left) side engine. It was frightening for many passengers. 3 or 4 the ground crew were trying to use rain umbrellas to shield the boarding passengers from the hot air blast as they climbed the boarding steps. I have made the same flight about 6 times, now, and this was to only time that I had experienced the severe noise, the hot engine exhaust, and the high velocity air blast. It all seemed to me that the port engine was responsible. If my facts are as I described them are correct, was the the boarding procedure a sanctioned and safe one?

donnf
 
T1a
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Re: ATR 72 Apron Safety

Thu Apr 26, 2018 5:22 pm

I've never flown the ATR, so I'm not 100% on all if this. But still pretty certain. The left engine on the ATR doesn't have a propeller brake, so if the engine was indeed on, the propeller would have been spinning at, at least, idle-feather speed; so I guess around 200rpm. If you didn't see the left propeller spinning at that speed, the engine was definitely not running. Having the right hand engine running in hotel mode during boarding is of course rather common, in case there is no ground-power or it is required for air-conditioning purposes.
Was it windy that day? Maybe you felt the blast from the right hand engine running in hotel mode that way blown underneath the fuselage and towards the boarding area?

If indeed the left hand engine was running during boarding this is way out of the ordinary for any aircraft type.

Cheers,
T1a
All views expressed under this username are mine as a private person and don't necessarily reflect the views of my employer.
 
VSMUT
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Re: ATR 72 Apron Safety

Fri Apr 27, 2018 12:15 am

donnf wrote:
Thanks for the feedback. Yes, loading was via the aft-rear door, after the passengers walked along the starbord side and around the tail. The noise, heat, and air blast that I and other passengers felt appeared to be coming from the port (left) side engine. It was frightening for many passengers. 3 or 4 the ground crew were trying to use rain umbrellas to shield the boarding passengers from the hot air blast as they climbed the boarding steps. I have made the same flight about 6 times, now, and this was to only time that I had experienced the severe noise, the hot engine exhaust, and the high velocity air blast. It all seemed to me that the port engine was responsible. If my facts are as I described them are correct, was the the boarding procedure a sanctioned and safe one?

donnf


I sounds very strange to let passengers walk on that side of the aircraft, even more so when in hotel mode. As for the procedure, ATR doesnt have one. It comes down to the national CAA or the individual operator. I myself wouldn't want passengers on that side of the aircraft for all sorts of reasons, this being just one of them. You also have a lot of the service vehicles, fuel truck/hoses and the GPU/power cable on that side.

Your description of the "blast" from the left engine is weird. Was the propeller spinning with several hundred RPM, or just very slowly? There is no inbetween on the left engine of an ATR, either it spins really fast or the engine isn't running at all.

One more thing, we dont use port and starboard in aviation. We use left and right. To avoid confusion (and I have a feeling that you might also have mixed them up) I suggest you do the same.
 
nws2002
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Re: ATR 72 Apron Safety

Fri Apr 27, 2018 4:07 pm

VSMUT wrote:
donnf wrote:
One more thing, we dont use port and starboard in aviation. We use left and right. To avoid confusion (and I have a feeling that you might also have mixed them up) I suggest you do the same.


Umm...every airline I worked for uses port and starboard.
 
Max Q
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Re: ATR 72 Apron Safety

Sun Apr 29, 2018 2:29 am

Were these airlines or shipping lines ?!


Port and Starboard are nautical terms not appropriate in aviation.


Let’s keep it simple, left and right works
well
The best contribution to safety is a competent Pilot.
 
rendezvous
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Re: ATR 72 Apron Safety

Sun Apr 29, 2018 2:49 am

If the left engine was running, the propeller would be spinning at a couple of hundred rpm as well. I would suggest that most airlines would not permit passengers nearby when a propeller is spinning, for obvious reasons. The ATR has a strap that connects the left propeller to the fuselage to prevent it spinning in the wind. Maybe this strap wasn't installed, so the propeller was spinning with the wind. The hot exhaust gasses may have been coming around the fuselage from the right hand engine.

The right engine can be used in hotel mode to provide power and air conditioning. The right hand propeller is hydraulically braked, and does not rotate while in hotel mode. Hotel mode is noisy, and does have hot exhaust gasses coming out the back of it - the exhaust itself usually isn't a problem. The operator I'm familiar with requires that the right door is closed prior to using hotel mode. When the propellor brake is released, the propeller starts spinning very quickly.
 
VSMUT
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Re: ATR 72 Apron Safety

Sun Apr 29, 2018 4:19 am

rendezvous wrote:
The ATR has a strap that connects the left propeller to the fuselage to prevent it spinning in the wind. Maybe this strap wasn't installed, so the propeller was spinning with the wind.


They don't normally get used during short turnarounds, and would typically be removed as one of the first things when the crew or ground staff reach the aircraft.
 
diverted
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Re: ATR 72 Apron Safety

Sun Apr 29, 2018 3:41 pm

VSMUT wrote:
rendezvous wrote:
The ATR has a strap that connects the left propeller to the fuselage to prevent it spinning in the wind. Maybe this strap wasn't installed, so the propeller was spinning with the wind.


They don't normally get used during short turnarounds, and would typically be removed as one of the first things when the crew or ground staff reach the aircraft.


Yeah, normally really only installed when the aircraft shuts down for the night, unless it's got lengthy ground time on a hard stand or something mid day
 
CanadianNorth
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Re: ATR 72 Apron Safety

Mon Apr 30, 2018 12:56 am

Max Q wrote:
Port and Starboard are nautical terms not appropriate in aviation.


I've worked on aircraft where the aircraft manuals straight from the manufacturer clearly state port and starboard. Aviation inherited many things from the nautical world, including port and starboard, red/green/white navigation lights, and the list goes on long enough to be its own topic in this forum.

Anyways, back on topic, the ATR "hotel mode" is only on the starboard / right / #2 engine. In hotel mode the prop should be stopped completely, if it's not then there is something wrong with the prop brake. The port / left / #1 engine is either running with the prop going probably at least a couple hundred RPM, or not running so the prop will be either stopped or slowly windmilling. Where I work the straps are usually only used when the aircraft will be on the ground for a while, usually put on after the last flight of the day and removed during preparation for the first flight of the day.

As far as passengers walking around the starboard / right side of the airplane I honestly can't think of any reason why any operator would do it like that. Especially with hotel mode running, where I work even employees are taught when hotel mode is going on the ATRs don't go near the starboard side unless you have a good reason to. The passengers are always guided around the port / left wing tip on their way to / from the passenger door regardless of hotel mode running or not. Passengers should never be near a running engine.

Based on 10+ years working full time in aviation, I'm going to go ahead and say umbrellas to block aircraft exhaust and/or propwash sounds like a terrible idea. I would highly recommend not doing that. If I saw that at work I'd very likely be submitting a safety report, and I'm the type that usually doesn't do reports unless I have a good reason to.
HS-748, just like a 747 but better!
 
oldannyboy
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Re: ATR 72 Apron Safety

Fri May 11, 2018 12:32 pm

Max Q wrote:
Were these airlines or shipping lines ?!


Port and Starboard are nautical terms not appropriate in aviation.


Let’s keep it simple, left and right works
well


Sorry, but yes they are. In English at least, port and starboard are the correct technical words. In technical manuals as well. And yes, they are borrowings from the nautical world.
Left and right cannot work simply because the perception of 'left' or 'right' changes depending from where you are looking at an object.

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