KLM Cityhopper E295 at Berlin on Sep 12th 2021, takeoff from 1320 meters past prepared line up

Last Update: September 24, 2023 / 20:14:41 GMT/Zulu time

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Incident Facts

Date of incident
Sep 12, 2021

Classification
Incident

Flight number
KL-1830

Aircraft Registration
PH-NXD

Aircraft Type
Embraer ERJ-195-E2

ICAO Type Designator
E295

Airport ICAO Code
EDDB

A KLM Cityhopper Embraer ERJ-195-E2, registration PH-NXD performing flight KL-1830 from Berlin Brandenburg (Germany) to Amsterdam (Netherlands) with 92 passengers and 5 crew, lined up runway 25R for departure via taxiway L5 and commenced takeoff becoming airborne at about the displaced threshold runway 07L. The aircraft continued to Amsterdam for a safe landing.

On Oct 14th 2021 the Dutch Onderzoeksraad (DSB, Dutch Safety Board) reported they were delegated the investigation into the occurrence by the German BFU. The DSB stated: "During take-off from runway 25R of Berlin Airport, the aircraft departed from another position than the crew had entered into the aircraft system. Consequently, the available runway length was 1,320 metres less than calculated."

ADS-B data show the KLM Embraer usually line up at taxiway L7 and commence takeoff from the displaced threshold of runway 25R, which provides 3300 meters/10,800 feet of available takeoff run (TORA) and available Accelerate-Stop Distance available (ASDA). After lining up via L5 the occurrence aircraft had only 1980 meters/6500 feet available for the takeoff run/accelerate and stop instead.

According to the Aerodrome Chart Line up via L7 provides for 3300 meters TORA/ASDA, whereas line up via L5 provides for 2065 meters TORA/ASDA.

On Sep 21st 2023 the Dutch Onderzoeksraad (DSB) released their final report concluding the probable causes of the serious incident were:

The Dutch Safety Board investigated the incident and found that the aircraft took off from Intersection L5 - as the crew intended - while the performance calculation was based on Intersection K5, because both pilots accidentally selected intersection K5 instead of L5 in the takeoff performance calculation application. The selection error resulted in a slower acceleration leading to a hazardous situation in which the aircraft became airborne 443 metres before the end of the runway.

The Dutch Safety Board found several contributing factors related to the selection error:

- Accidental misselections occur commonly when using a touchscreen tool with fingertouch interaction, especially if it is used routinely and therefore quickly. The lack of system feedback about the location of the finger and the ‘fat finger’ problem contribute to selection errors when working on a touchscreen.

- The takeoff performance calculation application does not provide visual feedback about the selected intersection and runway (airport synoptic).

- The pull down menu contains selection options (runway intersections) that are not normally used by the operator.

There were several contributing factors to the propagation of the misselection:

- The cross check did not reveal the selection error because the pilots likely only focused on the performance calculation outputs, which probably did not differ as both pilots had reportedly selected the same wrong intersection.

- Passing the sign indicating intersection L5 and the available runway length could not reveal the selection error either, because the crew had this intersection in mind. Also the calculated N1 was within range of expectation. Variant flying might have widened their range of expected performance parameters.

- The crew trusted the performance calculation application.

The DSB stated the runway data were for K5:

TORA 3,385 meters, TODA 3,445 meters, ASDA 3,385 meters

and for L5:

TORA 2,065 meters, TODA 2,125 meters, ASDA 2,065 meters

The DSB stated, that for taxiway K5 the following data were computed:

Flaps=1, Takeoff Mode 3, V1=139 KIAS, Vr=140 KIAS, V2=143 KIAS, Tass=57 deg. C

However, for taxiway L5 these data would have been correct:

Flaps=3, Takeoff Mode 3, V1=120 KIAS, Vr=121 KIAS, V2=124 KIAS, Tass=35 deg. C

The DSB analysed:

Factual information

The flight

On 12 September 2021, an Embraer 195-E2 with registration PH-NXD, was scheduled for a flight from Berlin Brandenburg Airport (EDDB, hereafter Berlin) in Germany to Amsterdam Airport Schiphol (EHAM, hereafter Schiphol) in the Netherlands. The scheduled departure time was 17.38 hours. The flight crew consisted of a captain and a first officer. The captain acted as pilot flying and the first officer as pilot monitoring. It was the third and last flight on the last day of the flight crew’s four-day schedule.

Flight preparation

After a short break between flights, the crew began their flight preparations and they planned from which runway intersection to take off. The crew expected a takeoff from Runway 25R and, after some discussion, they both agreed that intersection L5 was suitable in the prevailing weather conditions. The crew members stated that they did their takeoff performance calculation independently from each other by using the ePerf application on their Electronic Flight Bag (EFB). The pilots reported they compared the outcomes of their calculations: the takeoff mode, assumed temperature, flap position and takeoff speeds, see Table 1. They seemed to be realistic and within the range of what could be expected, according to the crew. After confirmation that the output parameters were identical, the data was entered into the Flight Management System (FMS).

Takeoff

After the ground controller issued the taxi clearance, the flight crew taxied from their stand B12 via Taxiway C towards intersection L5. The captain selected takeoff power.

The first officer, as pilot monitoring, noticed that the primary thrust indicator (N1) showed 75%. Although he considered this to be low, he believed it was correct. During the takeoff roll, he also felt the acceleration was slow and considered calling “full thrust”.

However, to avoid triggering the captain to abort the takeoff by a non-standard callout he did not do this. The captain also thought that the aircraft accelerated slower than he was accustomed to. He attributed this to the variant type. According to him, the Embraer 195 E2 accelerates a little slower than the other variants he is used to. Moreover, the E2 is more automated than the other variants and he believed the selected thrust was correct.

The crew stated that during the first part of the takeoff roll, the red lights at the end of the runway were not visible because the runway is slightly curved. At a certain point, the aircraft reached the takeoff decision and rotation speeds and the red runway end lights became visible. The distance to the red lights gave both crew members the impression that the aircraft became airborne with little runway length remaining.

When the aircraft was stabilised during the climb, the crew discussed what happened during and before takeoff. After checking the parameters, they found that they had both selected intersection K5 instead of L5 in the ePerf takeoff performance calculation application. After recalculation, they found that the assumed temperature should have been 35 °C instead of 57 °C and that Flaps 3 should have been set instead of Flaps 1.

Performance calculation for wrong intersection

The aircraft took off from intersection L5 while the performance calculation was based on intersection K5. Therefore the engine’s thrust and flap position were calculated and set for an available runway length (Take Off Run Available, TORA) of 3,385 metres. The acceleration of the aircraft to reach the calculated speeds V1 and Vr was also based on this distance. The actual TORA was 2065 metres, 1320 metres less. As a result, the acceleration of the aircraft was too slow to safely take off from intersection L5. This explains why the aircraft became airborne 443 metres19 before the end of the runway.

After the occurrence the aircraft manufacturer calculated that the aircraft would have been unable to stop on the runway in case the takeoff had to be aborted at, or just before, V1, which would have resulted in a runway excursion. The Accelerate Stop Distance (ASD) under the circumstances was 2565 metres while the Accelerate Stop Distance Available (ASDA), was 2065 metres. Furthermore, in case of an engine failure after V1 the aircraft would likely not have been able to attain the required climb performance. Therefore, the safety margins were reduced during the takeoff.

Intersection selection error

Data entry into ePerf is a routine operation that is often repeated. Therefore, the pilots entered the required information quickly. All available runways and corresponding entry points of the selected airport were listed in a pull down menu. This listing was in numerical and alphabetical order and Runway 25R K5 was listed just above 25R L5. Both crew members accidently touched and selected 25R K5 instead of 25R L5.

It is commonly understood that selection errors occur when working on a touchscreen with finger-touch interaction (tapping). Two factors explain the finger’s inaccuracy with tapping. First, there is no system feedback about the location of the finger prior to completing selections by tapping the screen. Second, the ‘fat finger’ problem means that the finger is a large and relatively crude pointing device for small targets. Items that are close to the desired target can be accidentally selected. Other incidents in which two crew members made the same error when selecting the runway and intersection have been investigated, namely the 2019 Nice incident and the 2015 Lisbon incident.

...

Pilot intervention

After the runway controller had issued the takeoff clearance, the flight crew lined up on the runway without stopping and selected takeoff power. Both crew members perceived a slower, but not unusual acceleration than expected.

The pilot flying thought slow acceleration was due to the difference between aircraft variants; he thought it was normal for the Embraer 195-E2 and believed that the thrust was calculated correctly. The pilot monitoring thought about giving the command “full thrust”. He did not do this, because he wanted to avoid triggering an unnecessary aborted takeoff. Pilots normally reject the takeoff for irregularities before V1 and do not select full thrust.

The crew realised something was wrong when the red lights at the end of the runway had become visible and the V1 and VR speeds were reached.

It is a well-known phenomenon that crew members do not select full thrust when the aircraft’s acceleration is less than expected. Full thrust was selected in one out of 23 occurrences involving the use of erroneous takeoff data, which were investigated by accident investigation boards in the period 2013-2021. ...

The final report dedicates two chapters to the Learning from this occurrence stating amongst others:

Limited learning from the occurrence

Although the seriousness of the incident was recognised at various levels of the operator’s organisation, the operator decided after a limited investigation (assessment) that further investigation into this occurrence was not necessary.

The limited investigation concluded that the outcome variability of the takeoff performance calculation tool contributed to the occurrence as well as a confusing runway intersection designation at Berlin Brandenburg Airport. Additionally, the pilots did not perceive any cues that would invalidate their state of mind and erroneous takeoff data was used for takeoff.

While the investigation by the Dutch Safety Board and the operator’s analysis cannot be compared, it does show that a more extensive investigation may yield greater understanding of the occurrence and mechanisms influencing the use of erroneous takeoff data. Moreover, the operator did not investigate any incidents regarding erroneous takeoff data although several incidents did occur and a safety concern had been formulated in the period 2012–2021. The operator’s approach of reducing the risk of erroneous takeoff data depends on specific topics that were investigated in predictive investigations with limited scope.

Metars:
EDDB 120920Z 28007KT 9999 SCT012 BKN016 19/16 Q1017 TEMPO BKN012=
EDDB 120850Z 27007KT 9999 SCT011 BKN016 19/16 Q1017 TEMPO BKN011=
EDDB 120820Z 28009KT 9999 SCT016 18/16 Q1017 NOSIG=
EDDB 120750Z 27009KT 9999 FEW016 BKN023 18/15 Q1017 NOSIG=
EDDB 120720Z 26007KT CAVOK 17/15 Q1016 NOSIG=
EDDB 120650Z 25006KT 210V270 CAVOK 17/15 Q1016 NOSIG=
EDDB 120620Z 23005KT CAVOK 16/14 Q1016 NOSIG=
EDDB 120550Z 23005KT CAVOK 16/14 Q1016 TEMPO 4000 BR=
EDDB 120520Z 23006KT CAVOK 15/14 Q1016 TEMPO 4000 BR=
EDDB 120450Z 22007KT CAVOK 15/14 Q1016 TEMPO 4000 BR=
EDDB 120420Z 24004KT CAVOK 14/14 Q1016 TEMPO 4000 BR=
Aircraft Registration Data
Registration mark
PH-NXD
Country of Registration
Netherlands
Date of Registration
Q pfbeqljgkf Subscribe to unlock
Airworthyness Category
Legal Basis
Manufacturer
Yaborã Indústria Aeronáutica S.A.
Aircraft Model / Type
ERJ 190-400
ICAO Aircraft Type
E295
Year of Manufacture
Serial Number
Aircraft Address / Mode S Code (HEX)
Maximum Take off Mass (MTOM) [kg]
Engine Count
Engine
CbhdhAlbkbgpbbglhbimkmpjqf gnAqiknckh ci Subscribe to unlock
Engine Type
Incident Facts

Date of incident
Sep 12, 2021

Classification
Incident

Flight number
KL-1830

Aircraft Registration
PH-NXD

Aircraft Type
Embraer ERJ-195-E2

ICAO Type Designator
E295

Airport ICAO Code
EDDB

This article is published under license from Avherald.com. © of text by Avherald.com.
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