Déja Vue ?
G’day
Embraer 145s have no problems with its brake system and the spoilers are not useless.
The landing performance challenges on the E145 without thrust reversers arise on contaminated runways combined with high approach speeds for this size of aircraft in the range of 130 to 145 KIAS and an aquaplaning speed in the range of 105 KIAS. In those conditions, the aircraft is demanding and there is no margin at all for errors, be it wrong friction coefficients, long flares, too high approach speeds etc.
The similar incident @ EDDS some of you are referring to occurred on January 26 2006 and involved a SWISS Embraer 145LU. Weather conditions at the time of the incident have been quite similar, i.e. ATIS info available to the crew was from 0650Z with RWY 07 ILS in use, Visibility 1400m in light snowfall , wind 120/1 with -3/-4°C and 1012hPa, VV not measurable, RWY Report wet with slush patches and BA good.
The SWISS crew elected to perform an approach with the Head Up Guidance System (HUGS) in AIII mode, i.e. landing Flap 22 were used (Flap 45 is full flap position and cannot be used for HUGS AIII approaches). With 3 crew and 40 Pax, landing mass was 18’600 kg (max landing mass E145LU is 19’300 kg) and corresponding approach speed was 138 KIAS. The A/C touched down on RWY 07 at 0717Z, 770m from the threshold at a speed of 128 KIAS. Two minutes before touchdown, tower advised the crew about “…be advised, BA medium” together with the landing clearance.
All E145s of SWISS were not fitted with thrust reversers, i.e. only aerodynamic drag plus carbon brakes available for deceleration. LDA for RWY07 is 3045m. The aircraft however, overran the RWY while the crew was trying to exit to the left via TWY A .The aircraft turned around the yaw axis and ended heading 210° about 60m in the grass between TWY A and threshold RWY25. No damage to the aircraft and ground equipment occurred.
Looking at the performance data of the SWISS E145s reveals that with a 19 ton aircraft in 0-wind conditions and BA good (according to ATIS) results in a landing distance of 1800m for flaps 22° on a 0%-slope runway. BA medium changes LD to 2800m ! A 1% down slope of the runway increases the LD by 15% in BA medium conditions. As EDDS RWY07 has between 0.7 and 0.9% downslope, adding 10% to the LD of a 0%-slope RWY yields 3080m. No way the SWISS could make it there…
The initial german aircraft accident investigation report (BFU) on the SWISS E145 incident in EDDS reveals that a B737-800 which landed shortly before the SWISS E145 reported after the landing to the tower that BA was initially “…medium” and then shorly after vacating the RWY into TWY A changed their grading to “…rather poor than medium”. Tower copied the info, however only transmitted “…be advised, BA medium” to the SWISS crew. For info, a BA medium to poor grading yields to roughly 3200m LD for an E145 without reversers.
Time 0544Z : EDDS Skiddometer measurements with A: 72 – B: 76 – C: 77
Time 0650Z : ATIS Info “BA good”
Time 0711Z : Info B737-800 to Tower “BA…rather poor than medium”
Time 0713Z : First contact of SWISS crew with EDDS tower
Time 0715Z : Landing clearance issued to SWISS crew with “…be advised, BA medium”
Time 0717Z : Touchdown on RWY07
Time 0722Z : New skiddo values measured shortly after the incident with A: 48 – B: 39 – C: 37
and values for sector C changing between 21 and 65 !
I am very keen to learn about final flap settings and most importantly what runway state info the crew received by the ATIS and by tower shortly before landing.