Hazard to ILS to runway 23 in BUF - Safety Alert 2009-1

C

CTFlyer

Well-Known Member
This is not meant as speculation to the recent crash - but is to notify and give a heads up to any pilots out there flying into BUF.

XX Pilots,

There is a potentially significant hazard concerning the ILS to runway 23 in BUF.

Information has been received indicating it is possible to obtain a significant nose pitch up, in some cases as much as 30 degrees, if the glide slope is allowed to capture before established on centerline. Pilots who are preparing to configure and land have the potential to experience abrupt pitch up, slow airspeed, and approach to stall if conditions present themselves in a certain manner.

This effect is the result of an earthen obstruction close enough to the ILS to affect the integrity of the glide slope signal. This has resulted in the issuance of an advisory given on ATIS which states that "the ILS Glide Slope for runway 23 is unusable beyond 5 degrees right of course."

When attempting to intercept the runway 23 ILS from right traffic, the ILS glide slope indication may read full deflection down. Just prior to intercept it may then move up in such as manner as to enable approach mode to capture in such a way as to result in a nose up pitch and loss of airspeed.

XX Airlines has issued a notice reading: "Until further notice, when executing the KBUF ILS/LOC Runway 23, DO NOT select Approach Mode until established on the localizer inbound."

This issue is being addressed on several levels in an attempt to address procedures, facilities, and communication regarding this matter. If you experience any issues related to this, please file an ASAP form and or call....
 
WTF???

This is getting crazier by the minute. The outcome was bad no matter what the cause but this possibility is from out of left field.
 
As far as the CRJ's autopilot, APPR mode won't capture glide slope until the loc is captured first.
 
No NOTAMs on this and can't find this message on the internet.

What's your source CTFlyer?
 
While I can neither confirm, nor deny the accuracy of CTflyer's statement.....
(the following is public information)
It should be noted that 3407 approached the localizer course from the Southeast. They were given headings of 310 and then 260 to join the course......this, obviously, would be to the LEFT of course.
 
Saab is the same way No Loc = No GS capture(I'm pretty sure every A/P is the same way). And yes they approached from the left. Don't know if this thread is a joke, but facts go a lot further in these situations.
 
I was in BUF back in November and shot the approach to 23. It seems like I remember that NOTAM being there even back then, but I could be mistaken. Anyway, the accident a/c was over the marker and turning to intercept when the problem occured, definitely within 5 degrees of the final approach course I would think.
 
I've seen glideslope capture pitches...SNA turning on from the north and lately at SEA on 16R due to unprotected glideslope. But nothing like 30 degrees.
 
For what it's worth, that bulletin was put out by SWAPA.

Related or just bad timing? Who knows right now.

In the CRJ I have seen the FD pitch up to about 20 degrees to capture a glideslope before. However it happens slow enough that you can normally dump the autopilot before it gets too bad.
 
I have seen the autopilot/FD chase an unprotected glideslope from 3degrees to over 10 degrees very abruptly. We quickly turned the AP off and did the rest by hand. Mine was over 10miles out, and we did get the PLI on the screen during recovery.
 
BobDDuck said:
For what it's worth, that bulletin was put out by SWAPA.

Related or just bad timing? Who knows right now.

In the CRJ I have seen the FD pitch up to about 20 degrees to capture a glideslope before. However it happens slow enough that you can normally dump the autopilot before it gets too bad.
Click to expand...

Weird.

In the 117..the only plane I've flown with A/P approach modes....I'd select a "LOC" mode to capture the Localizer, and don't select the "ILS" mode for the GS until gear down (since the GS antenna is inside the nose gear door, and the wheels come down at GSI. Still, if selected early, the plane will not climb to capture a GS initially, but will remain at alt until the command bar passes level, then once "captured", will follow it. I don't know if it had some logic to disregard the GS outside of 10 DME or not, but I do know if it didn't like the GS signal, it would give you a warning about it and revert to LOC mode. Happened a number of times to me that way.
 
BobDDuck said:
For what it's worth, that bulletin was put out by SWAPA.

Related or just bad timing? Who knows right now.

In the CRJ I have seen the FD pitch up to about 20 degrees to capture a glideslope before. However it happens slow enough that you can normally dump the autopilot before it gets too bad.
Click to expand...

I've seen the CRJ pitch up as well in one of those situations where the FMA claims it's captured the localizer (although we were still pretty far off course). It wasn't too dramatic, although we'd ballooned almost 150' by the time the capt clicked off the autopilot and leveled off. It was sort of spooky.
 
that NOTAM has been there as long as I can remember. And, if i remember correctly its the approach to 5 that tends to give some odd pitch changes when the AP is capturing. don't ever remember that on 23. of course theres a million little reason why this might happen, so I wouldn't even speculate this being a factor.
 
The 75/76 will capture a GS before LOC intercept. I have seen some pretty drastic pitch downs but never a pitch up. FWI, I only allow the AP to capture the GS prior to LOC intercept on a visual. Sometimes it helps but, usually I am hand-flying by this point.
 
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