Black hole approach to unfamiliar rural airport

[polaris]

It's a moonless, clear night in the rural Midwest, and you want to take a night flight to an unfamiliar airport. The runway does not have a precision approach (just a GPS approach over a river and a VOR-A approach), and the runway does not have VASI or PAPI lights. Is there any way to make this safe?

I did some reading and I saw that the black hole only becomes a problem if you decide to shoot a long straight-in approach (more than 2 miles). And that if you do a standard pattern entry and make the appropriate turns, you will be fine. Is this true?

Just a side story, but this situation arose a few weeks ago. I was scared, so I decided to land at another airport with an ILS approach (but no VASI/PAPI). During the final approach on about a 5-mile final, I ignored my HSI on purpose to see how accurately I could fly the approach visually. I thought I was doing a good job, but when I looked down at my HSI about 10 seconds later, it showed that I was way below the glide slope. This was a wake up call for me... the black hole illusion is REAL... even if you are fully aware of the potential for the illusion.

So my question is, is there a way to safely fly into an unfamiliar rural airport with a black hole approach (no precision approach, no VASI/PAPI) on a moonless, clear night?

 

[Geico266]

Not sure what you mean by black hole. Most airports have lights. Get the sight picture where you want it and the land airplane. Pretty simple.

 

[polaris]

Not sure what you mean by black hole. Most airports have lights. Get the sight picture where you wasn't it, land airplane. Pretty simple.

It happens in rural areas or over open water where there is little to no light on the ground. It's been a cause of many accidents.

http://www.avweb.com/news/airman/182402-1.html?redirected=1

 

[Jaybird180]

Black hole...try a pattern at your above conditions landing on runway 32
BTDT got the T-Shirt

 

[PilotAlan]

If the runway is long enough, what about a power off 180 abeam the numbers, aiming at 1/3rd of the way down the runway?
You stay in the airport environment, steep approach so you don't get low on approach, etc?

Never tried it, just thinking out loud.....

 

[Threefingeredjack]

No runway lights??? A VASI or PAPI shouldn't be required if you keep a good sight picture of the runway, even on a long straight in approach. From what I have read, over land the effect is most pronounced when departing from a lighted environment out over a dark area, but when I depart at night I just fly as if totally IFR. I know from personal experience you can get a little disoriented backing away from a flight deck and turning out over water at night, but again, that is why they put instruments in front of you.

 

[polaris]

No runway lights??? A VASI or PAPI shouldn't be required if you keep a good sight picture of the runway, even on a long straight in approach. From what I have read, over land the effect is most pronounced when departing from a lighted environment out over a dark area, but when I depart at night I just fly as if totally IFR. I know from personal experience you can get a little disoriented backing away from a flight deck and turning out over water at night, but again, that is why they put instruments in front of you.

There are runway lights, but that article talks about the illusion created by runway lights. I don't know-- just going off of the article

 

[PilotAlan]

So my question is, is there a way to safely fly into an unfamiliar rural airport with a black hole approach (no precision approach, no VASI/PAPI) on a moonless, clear night?

Personally, when flying to unfamiliar airports at night, I do a midfield crosswind at known TPA. The midfield and known location puts me at the centerline of the runway at known alt, so I can "set" my perspective of the lights (wider runways seem closer, narrow seem farther away, flying over "sets" in my brain what the lights should look like).

Then I'm in "normal" procedure with known distance from the runway on downwind, 45* to turn base, then turn final, with normal power settings and standard rate of descent.

So far, it's worked. Not saying there aren't potential problems, it's just what has worked so far.

 

[Geico266]

There are runway lights, but that article talks about the illusion created by runway lights. I don't know-- just going off of the article

Not when there are runway lights. Obviously be careful, but no reason to think you are going into a black hole. The runway lights give you the perspective of the site picture you are accustom to during the day. Vasi / papi are a waste of money for single engine aircraft, IMHO.

Best to go fly at night and check it out for yourself. I'm not trying to be braggadocios, just trying to convey what I have learned flying into unknown airports at night. If the lights are on go for it.

 

[poadeleted20]

Geico hit it -- practice in daylight until you know the sight pictures for approaching at glide path angles of 3-6 degrees and then nail it to the near end of the runway. And make sure that the near end lights never disappear from view behind any obstructions.

 

[Velocity173]

The runway light sight picture technique is only good if you're familiar with that airfield. Go from training in a class C with a 150 ft wide runway then over to a 60 ft wide with no surrounding lights and you could have some problems.

You could always use the descent chart in the back of the approach plate. Constant angle non precision approach (CANPA).

Or you could invest in SVT. Put your velocity vector on the end of the runway and keep it there.

 

[denverpilot]

Not only the items mentioned but do it the way pros do. Numbers numbers numbers.

Make yourself calculate safe altitudes for a pattern of your choosing and stay ABOVE them throughout the pattern.

The long straight in to a dark spot isn't the whole problem. It's not knowing exactly where you are and how high you MUST be at anyplace along that path.

 

[Neal Howard]

My home airport (rural) is the epitome of the "black hole" at night. It only has LIRL runway lights and is surrounded by brightly lit businesses and a state prison. You cannot see the runway lights until you're right on top of it, combined with the calm wind runway slopes downhill. You can easily find you way to "about where the airport is supposed to be" from a long way off but seeing the runway itself in the dark is quite a challenge.

I used to fly a lot at night in and out of it all the time in my Cherokee and made some of my most greaser landings at night here, but have totally given up night landings here now that I'm flying taildragger RVs. The old timers here have a saying: Don't fly at night because "The Boogerman comes out at night". I think I've finally become one of those "old timers" myself.

If I ever have to arrive here in W.Falls after dark, I'll go land at the other airport across town where it is lit up like a Christmas tree so brightly that landing lights are irrelevant and go fetch my airplane the next day in the daylight.

 

[bbchien]

Even a black hole approach to a familiar airport.

The answer, Take the INSTRUMENT approach.....every time. You are, for practical purposes, in IMC.

 

[Ted]

What Bruce said. I've done it before.

Also, to make things better, if you have WAAS you will probably get vertical guidance to help you with a glide path. I find this tremendously helpful, especially at my home airport at night.

 

[ZeroPapaGolf]

If the runway is long enough, what about a power off 180 abeam the numbers, aiming at 1/3rd of the way down the runway?
You stay in the airport environment, steep approach so you don't get low on approach, etc?

Never tried it, just thinking out loud.....

Not sure what the OP flies, but in my aircraft a power-off approach would be very ill advised. As is the case with most slick singles or heavier twins.

 

[weilke]

It's a moonless, clear night in the rural Midwest, and you want to take a night flight to an unfamiliar airport. The runway does not have a precision approach (just a GPS approach over a river and a VOR-A approach), and the runway does not have VASI or PAPI lights. Is there any way to make this safe?

In that particular case and in night VFR, I like to treat it as a circling approach. Fly the the approach, remain at TPA, overfly the field and then fly a tigh-in pattern pretty much over the airport. Also no shame in going around if you end up too high. I dont fly a jet. No need for a 'stabilized approach' and a 5 mile straight in final.

 

[Fearless Tower]

Geico hit it -- practice in daylight until you know the sight pictures for approaching at glide path angles of 3-6 degrees and then nail it to the near end of the runway. And make sure that the near end lights never disappear from view behind any obstructions.

The problem is that in his original post, he is talking about a night arrival to an unfamiliar airport.

You can practice and get the sight picture down all you want at your home airport, but it isn't necessarily going to look the same at the new airport (length/width differences, slope..etc).

For me, if it is an unfamiliar airport and I am arriving for the first time at night, I would much prefer an IAP.

 

[Piloto]

The Garmin Aera 560 will provide vertical guidance (G/S) on the synthetic HSI and on the map to airports or locations with no approach defined. You can also get lateral guidance by setting the OBS to the runway bearing. It works in the same way as an instrument approach. Combined with the terrain function you have a very good idea of where you are. A very handy unit specially for remote fields.

José

 

[weilke]

The Garmin Aera 560 will provide vertical guidance (G/S) on the synthetic HSI and on the map to airports or locations with no approach defined.

That vertical guidance will happily guide you into a hill short of the runway. It is just a geometrical model that knows nothing about obstacle planes.

 

[bbchien]

The Garmin Aera 560 will provide vertical guidance (G/S) on the synthetic HSI and on the map to airports or locations with no approach defined. You can also get lateral guidance by setting the OBS to the runway bearing. It works in the same way as an instrument approach. Combined with the terrain function you have a very good idea of where you are. A very handy unit specially for remote fields.

José

GAWD....see Weilke's comment.

 

[Jeanie]

We have this problem here in this part of Texas. Yes, if you fly a regular pattern using the same power settings as usual into a dark airport you will be ok. Don't us the numbers as an aiming point... Plan to land on the 1000 ft. Markers if available. That is, don't think you have to land on the numbers, landing long is a good thing.

If there is an instrument approach that you feel comfortable with then use that. But, really just entering the pattern like normal and keeping the base final tight is fine.

 

[Clip4]

It's a moonless, clear night in the rural Midwest, and you want to take a night flight to an unfamiliar airport. The runway does not have a precision approach (just a GPS approach over a river and a VOR-A approach), and the runway does not have VASI or PAPI lights. Is there any way to make this safe?

I did some reading and I saw that the black hole only becomes a problem if you decide to shoot a long straight-in approach (more than 2 miles). And that if you do a standard pattern entry and make the appropriate turns, you will be fine. Is this true?

Just a side story, but this situation arose a few weeks ago. I was scared, so I decided to land at another airport with an ILS approach (but no VASI/PAPI). During the final approach on about a 5-mile final, I ignored my HSI on purpose to see how accurately I could fly the approach visually. I thought I was doing a good job, but when I looked down at my HSI about 10 seconds later, it showed that I was way below the glide slope. This was a wake up call for me... the black hole illusion is REAL... even if you are fully aware of the potential for the illusion.

So my question is, is there a way to safely fly into an unfamiliar rural airport with a black hole approach (no precision approach, no VASI/PAPI) on a moonless, clear night?

Yes, fly the approach, remain at the circling to land altitude, and descend using a steep descent angle within the protected area on final.

 

[denverpilot]

I think I'll just circle the airport until I run out of gas then spiral to a landing midfield.



(The thread is headed for "stupid". I think I'll just kick the ball and overcome the inertia stopping it from rolling.)

 

[Immelman]

Black hole flying is practically IMC. Without moonlight or an otherwise discernible horizon it IS IMC.

Fly the approach....that's simple enough, but what about getting from the MDA to the runway? Assuming the procedure is a straight-in, use either a charted visual descent point (VDP), or make your own (called by some a PDP, precision descent point).

If there is a charted VDP, use it! If not, roll your own descent point: The 300'/mile rule works well here if you have GPS/DME to identify where the runway begins. In absence of distance information (timed approach to identify the missed approach point), take your MDA HAT/10 - leave MDA at that time in seconds. e.g. MDA is 500' above the runway, leave the MDA with 50 seconds to go on your count-down timer...

 

[Henning]

It's a moonless, clear night in the rural Midwest, and you want to take a night flight to an unfamiliar airport. The runway does not have a precision approach (just a GPS approach over a river and a VOR-A approach), and the runway does not have VASI or PAPI lights. Is there any way to make this safe?

I did some reading and I saw that the black hole only becomes a problem if you decide to shoot a long straight-in approach (more than 2 miles). And that if you do a standard pattern entry and make the appropriate turns, you will be fine. Is this true?

Just a side story, but this situation arose a few weeks ago. I was scared, so I decided to land at another airport with an ILS approach (but no VASI/PAPI). During the final approach on about a 5-mile final, I ignored my HSI on purpose to see how accurately I could fly the approach visually. I thought I was doing a good job, but when I looked down at my HSI about 10 seconds later, it showed that I was way below the glide slope. This was a wake up call for me... the black hole illusion is REAL... even if you are fully aware of the potential for the illusion.

So my question is, is there a way to safely fly into an unfamiliar rural airport with a black hole approach (no precision approach, no VASI/PAPI) on a moonless, clear night?

If there are runway lights, it's quite simple to make a safe approach. There is no real difference in day or night, as long as all the perspective lines remain stable and the threshold is slowly descending in the windshield, you're fine. Your landing lights will illuminate the ground for the final finesse work.

 

[Jeff K]

It's a moonless, clear night in the rural Midwest, and you want to take a night flight to an unfamiliar airport. The runway does not have a precision approach (just a GPS approach over a river and a VOR-A approach), and the runway does not have VASI or PAPI lights. Is there any way to make this safe?

Wow.... Deja Vu... it was almost a year ago a pilot killed himself at my new home airport. I remember it well because I landed about 15 minutes before him.

It was a calm, hazy and moonless night... I knew the PAPI's where out of service on runway 28 (whose final is over dark farmland) so I picked runway 10 where the final in part is over the town (lights). The accident pilot came in later on runway 28, and with no PAPI's ended up clipping some trees. The terrain to the east also rises... which didn't help.

I've flown this approach 100's of times and it still gives me the willies. All I can say for advice without the PAPI's working I just make a high approach and accept the fact I won't be turning off at midfield to the taxiway.

--

P.S.

It happens in rural areas or over open water where there is little to no light on the ground. It's been a cause of many accidents.

http://www.avweb.com/news/airman/182402-1.html?redirected=1

I read the above article and it almost exactly describes the accident I mentioned above:

Some conditions make the black hole effect more pronounced. Be alert for the illusion when you observe these conditions:

An airport that is on the near side of a brightly lit city with few or no terrain features or lights between you and the airport. The brightness of the city lights will give the impression that they are closer than they are.

 

[Fearless Tower]

That vertical guidance will happily guide you into a hill short of the runway. It is just a geometrical model that knows nothing about obstacle planes.

No kidding.

You could ask the crew of UPS 1354 how well that concept works.....oh wait, you can't....they're dead.

 

[RV10flyer]

It helps to read this too...

PORTSMOUTH, OH
GREATER PORTSMOUTH RGNL (PMH)
AMDT 3 12152 (FAA)
TAKEOFF MINIMUMS: Rwy 18, 300-1¾ or std. w/min.
climb of 257' per NM to 1100.
DEPARTURE PROCEDURE: Rwy 18, climb heading
170° to 1300 before proceeding on course.
NOTE: Rwy 18, trees beginning 4' from DER, 290' left
of centerline, up to 100' AGL/721' MSL. Trees
beginning 678' from DER, 495' right of centerline, up
to 100' AGL/931' MSL. Rwy 36, trees beginning 1'
from DER, 180' left of centerline, up to 100' AGL/780'
MSL. Trees beginning 687' from DER, 388' right of
centerline, up to 100' AGL/710' MSL.

 

[Geico266]

OP, another technique I use at night I'd to use the middle of the runway. Don't land on the numbers, land down the runway a ways. Use the whole runway at night. Usually the winds are low at night so IMHO it is okay to float a little to set the plane down gently.

Practice and experience my friend, they are your best CFI now.

 

[azure]

The only airport without an IAP or PAPI that I'll consider landing at after dark is 3DA, and only because I know it pretty well. Even then, only on 18 because the north end of the runway terminates at a road and it's fairly well lit. At 76G, I will land on 22 at night for the same reason, but normally 22 has a PAPI. For many years the PAPI on 4 was OTS. There are p-lines on short final, so no thanks, I'll take a downwind landing on 22 (and the airport manager's ire) over that risk.

A black hole approach without a PAPI? Forget it. 23 at HYX comes to mind. It's a rectangle of runway lights surrounded by pitch blackness. The one time I landed there, I was grateful for the PAPI. If the PAPI were out, I'd land on a different runway, or else go somewhere else.

 

[Piloto]

That vertical guidance will happily guide you into a hill short of the runway. It is just a geometrical model that knows nothing about obstacle planes.

Obviously you have no experience flying with the Aera 560 or with TAWS (Terrain Alert Warning System). Here in Florida the TAWS in the 560 accurately alert me of towers in my flight path when flying underneath Class B airspace or underneath the weather. Same for terrain in hilly topography. It also depicts a profile view of the terrain along your flight path. The terrain or obstacle icon will change to red when it will intercept your flight path.

More about TAWS at: http://en.wikipedia.org/wiki/Terrain_awareness_and_warning_system

José

 

[Turningfinal]

Not when there are runway lights. Obviously be careful, but no reason to think you are going into a black hole. The runway lights give you the perspective of the site picture you are accustom to during the day. Vasi / papi are a waste of money for single engine aircraft, IMHO.

Try flying into my home airport at night without the VASI, and you'll likely find yourself in the 20 foot hedges located just off the runway end.

 

[weilke]

Obviously you have no experience flying with the Aera 560 or with TAWS (Terrain Alert Warning System). Here in Florida the TAWS in the 560 accurately alert me of towers in my flight path when flying underneath Class B airspace or underneath the weather. Same for terrain in hilly topography. It also depicts a profile view of the terrain along your flight path. The terrain or obstacle icon will change to red when it will intercept your flight path.

Well that's true genius right there, basically nothing that could go wrong with that approach.

 

[stratobee]

Let me share a VFR night approach I did about 2 years ago in my old Commander twin, which was similarly disorienting to the OP's. I'd gotten spoiled with night flying over lit up urban areas and it took this experience to realise how disorienting night VFR flying can be in rural areas. It was a good lesson and I now regard all night VFR as semi-IFR.:

I needed to be at Inoykern Airport in the Owen's Valley by the next morning for a job. Inoykern is in the high desert, surrounded to the west by the mighty Sierra Nevadas (with peaks well above 14K feet) and to the left by the biggest military restricted area in California. It's squeezed in between a rock and a hard place, literally. The drive by car was closer to 4hrs, so I'd decided early on to fly. Unfortunately, my days work in LA dragged on and it was 9pm before I could get out to the airport and get going. By now it was obviously pitch black. WX was good, but I was tired and I should in all honesty have left early the morning after instead, but that would have made me vulnerable time wise should any snags develop. I guess the time pressure got to me. Anyway, for the first 30 mins out, with all the lights beneath me from SF Valley and Palmdale, it was dead easy and similar to much other night flying I'd done. But just past Mojave the lights go away, and the terrain is not only rising, you're coming up to the foothills of the Sierras. You need to be on point with your navigation, or you'll end up a mountainside ornament.

I followed the road up through the mountains at good altitude, but it was late on a weekday, so visual references were far and few between (i.e. no cars) and also single point. Finally, the PTT lit the airport up with its three rwy's like a Christmas tree in the distance - a welcome sight. The airport is right on the restricted airspace line, so I set up for a right downwind as per published procedure. Afraid to bust the R, and afraid to get too low, I realise I've turned final way too early and am way too high. As much as I try, I'm not going to make it down even on this long rwy. It was time to go around. But as soon as I turn right crosswind, all my references go away and I'm left with nothing but pitch blackness low to the ground. The rwy lights fade away as they time out and I can see the glow go out in the reflections under my nacelles. Now I was facing rising terrain and the Sierras out there in darkness as I continued my turn to the downwind. It felt like the turn took forever and that earth was going to come up and grab me. The temptation is to increase the bank to keep it tight, which can have unpleasant consequences. It was like being inside a black bag at the bottom of the deepest sea trench. Afraid to do the same mistake again and be too high, but also fighting the feeling of rising terrain coming up to smythe me, I had to trust that the VFR chart was correct, that I wasn't too far off. My instinct was to climb, climb, climb and get away from earth (which, undoubtedly, is better than the opposite). It was very disorienting without any visual cues. Thankfully, I had some basic instrument training by then, and just steeled myself to trust what they said. I decided I'd rather bust the R a little than have to do another go around, so I extended a bit more. I came in better, but it was still that "black hole" feeling on final when you don't really know if you're high enough to clear terrain, or too low or what, and the rwy lights are blinding you.

I was very happy to be on the ground after that second approach.

 

[polaris]

Let me share a VFR night approach I did about 2 years ago in my old Commander twin, which was similarly disorienting to the OP's. I'd gotten spoiled with night flying over lit up urban areas and it took this experience to realise how disorienting night VFR flying can be in rural areas. It was a good lesson and I now regard all night VFR as semi-IFR.:

I needed to be at Inoykern Airport in the Owen's Valley by the next morning for a job. Inoykern is in the high desert, surrounded to the west by the mighty Sierra Nevadas (with peaks well above 14K feet) and to the left by the biggest military restricted area in California. It's squeezed in between a rock and a hard place, literally. The drive by car was closer to 4hrs, so I'd decided early on to fly. Unfortunately, my days work in LA dragged on and it was 9pm before I could get out to the airport and get going. By now it was obviously pitch black. WX was good, but I was tired and I should in all honesty have left early the morning after instead, but that would have made me vulnerable time wise should any snags develop. I guess the time pressure got to me. Anyway, for the first 30 mins out, with all the lights beneath me from SF Valley and Palmdale, it was dead easy and similar to much other night flying I'd done. But just past Mojave the lights go away, and the terrain is not only rising, you're coming up to the foothills of the Sierras. You need to be on point with your navigation, or you'll end up a mountainside ornament.

I followed the road up through the mountains at good altitude, but it was late on a weekday, so visual references were far and few between (i.e. no cars) and also single point. Finally, the PTT lit the airport up with its three rwy's like a Christmas tree in the distance - a welcome sight. The airport is right on the restricted airspace line, so I set up for a right downwind as per published procedure. Afraid to bust the R, and afraid to get too low, I realise I've turned final way too early and am way too high. As much as I try, I'm not going to make it down even on this long rwy. It was time to go around. But as soon as I turn right crosswind, all my references go away and I'm left with nothing but pitch blackness low to the ground. The rwy lights fade away as they time out and I can see the glow go out in the reflections under my nacelles. Now I was facing rising terrain and the Sierras out there in darkness as I continued my turn to the downwind. It felt like the turn took forever and that earth was going to come up and grab me. The temptation is to increase the bank to keep it tight, which can have unpleasant consequences. It was like being inside a black bag at the bottom of the deepest sea trench. Afraid to do the same mistake again and be too high, but also fighting the feeling of rising terrain coming up to smythe me, I had to trust that the VFR chart was correct, that I wasn't too far off. My instinct was to climb, climb, climb and get away from earth (which, undoubtedly, is better than the opposite). It was very disorienting without any visual cues. Thankfully, I had some basic instrument training by then, and just steeled myself to trust what they said. I decided I'd rather bust the R a little than have to do another go around, so I extended a bit more. I came in better, but it was still that "black hole" feeling on final when you don't really know if you're high enough to clear terrain, or too low or what, and the rwy lights are blinding you.

I was very happy to be on the ground after that second approach.

Thanks for the story. And for everyone else's tips. After reading everyone's post, I will keep the following list of preferences in mind for black hole approaches (I am a single-engine Cessna):

1. Precision approach OR VASI/PAPI to the landing runway, if available.
2. Instrument approach to any runway or midfield, if available, then circle to land OR do the math like the pros and determine descent rate and appropriate altitude at certain distances before the runway threshold.
3. Fly a standard pattern at known TPA to establish visual references, then fly a tight traffic pattern OR do a power-off 180 abeam the numbers.

*Always try to land beyond the 1000 ft markers if long runway.

 

[flyingcheesehead]

Sounds like there are a lot of people here who don't know what a black hole approach really is.

 

[Palmpilot]

The runway light sight picture technique is only good if you're familiar with that airfield. Go from training in a class C with a 150 ft wide runway then over to a 60 ft wide with no surrounding lights and you could have some problems...

Couldn't you just put the threshold lights at the normal position on the windscreen, using your normal descent configuration, and ignore the apparent width of the runway light pattern?

 

[denverpilot]

It helps to read this too...

PORTSMOUTH, OH
GREATER PORTSMOUTH RGNL (PMH)
AMDT 3 12152 (FAA)
TAKEOFF MINIMUMS: Rwy 18, 300-1¾ or std. w/min.
climb of 257' per NM to 1100.
DEPARTURE PROCEDURE: Rwy 18, climb heading
170° to 1300 before proceeding on course.
NOTE: Rwy 18, trees beginning 4' from DER, 290' left
of centerline, up to 100' AGL/721' MSL. Trees
beginning 678' from DER, 495' right of centerline, up
to 100' AGL/931' MSL. Rwy 36, trees beginning 1'
from DER, 180' left of centerline, up to 100' AGL/780'
MSL. Trees beginning 687' from DER, 388' right of
centerline, up to 100' AGL/710' MSL.

Huh. Look at that. Numbers. Just like I said. Amazing.

 

[polaris]

Couldn't you just put the threshold lights at the normal position on the windscreen, using your normal descent configuration, and ignore the apparent width of the runway light pattern?

I think the issue is that, because there are no features around the blackhole runway, you cannot orient yourself just by visual references. Of course you can use numbers. But most people go visual because it's VFR. If visual, you may not know whether you are actually on the right glide path until it's too late. See the attached picture. You could be on any of the glide paths below and you may not know which glide path you are actually on because the runway width would look the same whether you are at A, B or C. If you are at C and there are trees at the end of the runway, you are f-ed. Of course, if you know the numbers, you will not have this problem.