Narrative:

Right traffic for runway 23 buf. When given an intercept for the ILS 23; we noted a 'false GS' indication. Since I had read the bulletin; I did not select 'approach' until established on the localizer; even though we had been cleared for the approach prior to localizer capture. Normal procedures call for 'cleared for the approach select/request approach mode.' the 'false GS' indications occurred exactly as described in the memo. 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 GS 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 GS signal. This has resulted in the issuance of an advisory given on ATIS which states that 'the ILS GS for runway 23 is unusable beyond 5 degrees right of course.' when attempting to intercept the runway 23 ILS from right traffic; the ILS GS indication may read full deflection down. Just prior to intercept it may then move up in such a manner as to enable approach mode to capture in such a way as to result in a nose-up pitch and loss of airspeed. Flight crew suggestions/narrative: there is a briefing note on the approach plate noting that the GS is unusable beyond 5 degrees right of course. This small note could be missed during the approach briefing. The 'approach selection procedures' for buf runway 23 would enhance safety for IMC operations if included on the buf airport advisory page.

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Original NASA ASRS Text

Title: B757 Captain notes that the glideslope to Runway 23 at BUF is unusable beyond 5 degrees right of the LOC and may be dangerous when flying a coupled approach. Suggests that stronger language and procedure modification may be in order for this runway in the tailored briefing pages.

Narrative: Right traffic for Runway 23 BUF. When given an intercept for the ILS 23; we noted a 'False GS' indication. Since I had read the bulletin; I did not select 'Approach' until established on the LOC; even though we had been cleared for the approach prior to LOC capture. Normal procedures call for 'Cleared for the approach select/request Approach Mode.' The 'False GS' indications occurred exactly as described in the memo. 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 GS 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 GS signal. This has resulted in the issuance of an advisory given on ATIS which states that 'the ILS GS for Runway 23 is unusable beyond 5 degrees right of course.' When attempting to intercept the Runway 23 ILS from right traffic; the ILS GS indication may read full deflection down. Just prior to intercept it may then move up in such a manner as to enable approach mode to capture in such a way as to result in a nose-up pitch and loss of airspeed. Flight crew suggestions/narrative: There is a briefing note on the approach plate noting that the GS is unusable beyond 5 degrees right of course. This small note could be missed during the approach briefing. The 'Approach selection procedures' for BUF Runway 23 would enhance safety for IMC operations if included on the BUF Airport advisory page.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.