Ryanair B738 at Eindhoven on May 31st 2013, unstable approach, loss of speed during go-around

A Ryanair Boeing 737-800, registration EI-ENL performing flight FR-3531 from Palma Mallorca,SP (Spain) to Eindhoven (Netherlands) with 126 passengers and 6 crew, was on final approach to Eindhoven's runway 21 at about 08:48L (06:48Z) when the crew initiated a go-around. The aircraft positioned for another approach to runway 21 and landed safely 12 minutes later.

The Dutch Onderzoeksraad (DSB, Dutch Safety Board) reported on Jun 19th, that on May 31st 2013 a Boeing 737-800 went around at Eindhoven, during the go-around the speed decreased. The aircraft proceeded for a safe landing on its second approach. An investigation has been opened into the occurrence.

The airline reported that the crew disconnected the autopilot and went around due to an unstable approach and proceeded for a safe landing on the second approach 12 minutes later. The Irish Aviation Authority has been informed about the occurrence and assists the Dutch Safety Board in the investigation of the occurrence.

The Dutch Onderzoeksraad released a safety warning in Dutch stating, that intercepting the glidepath of an ILS from above the glidepath can lead to the autopilot capturing the wrong (mirror) glidepath, for a standard ILS glidepath at 3 degrees there MAY be a mirror glidepath at 6 degrees however with reversed indications and at 9 degrees a mirror glidepath indicating normally. Intercept such a mirror glidepath can lead to the autopilot substantially and unexpectedly pitching the aircraft. The DSB argued, that they are investigating an incident of 2013 in Eindhoven, where the aircraft suddenly took a very high nose up attitude while on an ILS approach leading to a sharp decrease of airspeed until the stick shaker activated. Then the crew initiated a go-around. The DSB stated that depending on the type of ILS being used there may be glidepath reversal indications outside the protected glidepath angle which would upon the aircraft going above that mirror glidepath resulting in a too low indication prompt the autopilot to increase the nose attitude until elevator and stabilizer reach their maximum nose up deflections. The reversed mirror glideslope at 6 degrees is not observed on all types of ILS glidepath transmitters. During test flights at two aerodromes in the Netherlands such reversed indications were tested, it was found that very quick action by crew was needed to return the aircraft to normal flight upon encountering reversed glidepath indications with autopilot engaged in approach mode. The DSB also referred to a BEA report, see Report: Air France A343 at Paris on Mar 13th 2012, intercepted mirror glide slope, large pitch oscillations and approach to stall.

Eindhoven offers a runway 03/21 of 3000 meters/9840 feet length featuring ILS Category I (OCH 185 feet for runway 03, OCH 179 feet for runway 21) and NDB/DME approaches to both runways 03 and 21.

Metars:

EHEH 310813Z AUTO 32009KT 7000 BR BKN160 16/13 Q1010 WHT 34012G23KT 7000 FEW012BKN160

EHEH 310755Z AUTO 32010KT 6000 BR FEW007 SCT010 SCT013 15/13 Q1010 GRN 32010KT 6000 SCT010 BECMG 34012G23KT CAVOK

EHEH 310734Z AUTO 33009KT 5000 BR FEW006 15/13 Q1010 WHT 32010KT 5000 BR SCT007BECMG 34012G23KT CAVOK

EHEH 310733Z AUTO 33009KT 5000 BR SCT006 15/13 Q1010 YLO 32010KT 5000 BR SCT007BECMG 34012G23KT CAVOK

EHEH 310725Z AUTO 33009KT 4100 BR BKN006 BKN007 14/13 Q1010 YLO 32010KT 5000 BR SCT007 BECMG 34012G23KT CAVOK

EHEH 310655Z AUTO 32009KT 2700 R03/2700U BR BKN003 OVC005 13/12 Q1010 YLO 32009KT 3000 BR BKN005 OVC007 BECMG 33012G23KT 9999 NSW FEW008 BKN200

EHEH 310625Z AUTO 32008KT 1900 R03/1900N BR OVC003 12/12 Q1010 YLO 32009KT 2000 BR BKN003 OVC005 BECMG 33011G22KT 5000 NSW FEW005 BKN200

EHEH 310614Z AUTO 32009KT 1800 R03/1800N BR OVC003 12/12 Q1010 YLO 32009KT 1500BR BKN002 OVC003 BECMG 3000 BKN004 OVC005

EHEH 310613Z AUTO 32008KT 1800 R03/1800N BR OVC002 12/12 Q1010 AMB 32009KT 1500BR BKN002 OVC003 BECMG 3000 BKN004 OVC005

EHEH 310603Z AUTO 31008KT 1700 R03/1700N BR OVC002 12/12 Q1010 AMB 32009KT 1500BR BKN002 OVC003 BECMG 3000 BKN004 OVC005

EHEH 310555Z AUTO 31009KT 1600 R03/1600N BR BKN002 12/11 Q1010 AMB 32009KT 1500 BR BKN002 OVC003 BECMG 3000 BKN004 OVC005

EHEH 310525Z AUTO 32008KT 1400 R03/1400D BR OVC002 11/11 Q1010 AMB 32009KT 1500 BR BKN002 OVC003 BECMG 3000 BKN004 OVC005

EHEH 310516Z AUTO 32008KT 1500 R03/1500N BR BKN002 11/11 Q1010 AMB 32009KT 2000BR SCT004 OVC005 TEMPO 1500 SCT002 OVC004

EHEH 310510Z AUTO 32008KT 1700 R03/1700N BR BKN002 11/11 Q1010 AMB 32009KT 2000BR SCT004 OVC005 TEMPO 1500 SCT002 OVC004

EHEH 310500Z AUTO 31007KT 1700 R03/1700D BR OVC003 11/11 Q1010 YLO 32009KT 2000BR SCT004 OVC005 TEMPO 1500 SCT003 OVC004

EHEH 310455Z AUTO 32008KT 1900 R03/1900N BR OVC003 12/11 Q1010 YLO 33010KT 2000 BR SCT004 OVC005 TEMPO SCT003 OVC004

EHEH 310449Z AUTO 32008KT 2000 R03/2000N BR OVC003 11/11 Q1010 YLO 33010KT 2000BR SCT004 OVC005 TEMPO SCT003 OVC004

EHEH 310436Z AUTO 32008KT 2000 R//////// BR OVC003 12/11 Q1010 YLO 33010KT 2000BR SCT004 OVC005 TEMPO SCT003 OVC004

EHEH 310425Z AUTO 32010KT 2200 BR OVC003 12/11 Q1010 YLO

EHEH 310355Z AUTO 32009KT 2500 -RA OVC004 12/11 Q1009 YLO