20-0887 Z1 EN V03

Bundesstelle fürFlugunfalluntersuchung German Federal Bureau of Aircraft Accident Investigation

Interim Report Identification

Type of Occurrence: Serious Incident

Date: 10 October 2020

Location: Frankfurt-Main

Aircraft: Airplane

Manufacturer: The Boeing Company

Type: 777F

Injuries to Persons: No injuries

Damage: Aircraft not damaged

Other Damage: None

State File Number: BFU20-0887-5X

Abstract

After take-off, the flight crew noticed unreliable indicated airspeed values and de-

clared emergency. In order to not exceed the maximum landing mass, several tons of

fuel were dumped and after about one hour of flight time the airplane landed again at

the aerodrome of departure. After the landing, it was determined that the sensors of

the left and right static systems were not connected.

Interim Report BFU20-0887-5X

- 2 -

Factual Information

History of the Flight

Prior to the flight, the 777F had been subject to different scheduled maintenance

work lasting several days. One work package included the following tasks on the pi-

tot-static system:

Flushing the connecting lines

Leak test and system test

Four pilots were on board for the flight from Frankfurt am Main to Shanghai, China.

The co-pilot was pilot flying, the commander pilot monitoring.

At 0921:31 hrs1, the airplane took off from runway 25C with an indicated airspeed of

204 kt and a ground speed of 191 kt.

Approximately 15 seconds later, the FDR and the CVR recorded wind shear warning.

At the time, indicated airspeed was 176 kt and ground speed 199 kt. The co-pilot re-

quested: “Max Thrust”. The commander confirmed this. He reported the wind shear

warning to ATC and added: “[…] we have now five-zero knots tailwind […]”. Pitch an-

gle decreased slowly from 11° to 7°. After another approximately 10 seconds, the

commander requested the co-pilot to increase the pitch angle. The co-pilot answered

that she did not want to fall below the stipulated speed. At this time, indicated air-

speed was 178 kt. The commander noticed the tailwind had increased to 80 kt. Both

showed surprise that with full thrust it was not possible to reach the required speed

even though pitch angle was already unusually low. After the indicated tailwind had

increased to 100 kt, the commander reasoned: “[…] also, das kommt mir sehr

komisch vor, ich würd‘ sagen, das is‘ (this is very strange, I would say this is) unrelia-

ble airspeed.”

Commander and co-pilot agreed to switch their roles of pilot monitoring and pilot fly-

ing and the commander took over controls.

Shortly afterwards, the co-pilot noticed that the Integrated Standby Flight Display in-

dicated a speed of 300 kt. At that time, the FDR recorded a ground speed of also

300 kt.

1 All times local, unless otherwise stated.


- 3 -

After the crew unanimously agreed that the airspeeds indicated at the 2 Primary

Flight Displays were unreliable values, at 0923:20 hrs, the commander decided to

declare emergency and stabilise the flight attitude with pitch angle changes. At the

time, the aircraft was about 8 NM south-west of the aerodrome of departure at about

6,000 ft2. The flight path above ground is based on FDR data and depicted in Fig-

ure 1.

Subsequently, flight crew and air traffic controller coordinated the flight path. Accord-

ing to the CVR, the aircraft was for long distances at an altitude band between

6,000 ft and 8,000 ft. The heading led the aircraft back to Frankfurt Main and from

there about 50 NM north-east over VOR Metro. At 0940 hrs, the crew began to dump

fuel as agreed with ATC in order to reduce the mass of the aircraft to the maximum

allowable landing mass. Approximately 5 min later, the aircraft turned to a heading of

about 250° and maintained it for 55 NM. At 1002 hrs, the aircraft turned to about

210°. At 1011 hrs, fuel dumping ended. Subsequently, ATC guided the airplane to

the ILS approach of runway 07C at Frankfurt Main Airport. At 1023:15 hrs, it touched

down and taxied to the parking position accompanied by the airport fire brigade.

2 The crew had read the altitudes given in this report at the Integrated Standby Flight Display, there-fore they were documented on the CVR.


- 4 -

Personnel Information

Commander

The 44-year-old PIC held an Airline Transport Pilot Licence (ATPL(A)), initially issued

on 28 January 2015 in Germany in accordance with Part-FCL. The licence listed the

following type ratings: B777/787 as PIC, IR valid until 31 August 2021 and MD11 as

PIC, IR valid until 31 November 2020.

He also held the instructor rating for B777/787 (TRI rp) and MD11 (TRI) as well as an

aerobatics rating.

His medical certificate pertaining to a Part-FCL licence was issued on

13 November 2019. His class 1 medical certificate was valid until 10 December 2020.

Fig. 1: Flight path based on FDR data Source: OpenFlightMaps.org / adaptation BFU


- 5 -

2. Commander

The 56-year old 2nd commander held an Airline Transport Pilot Licence (ATPL(A)) ini-

tially issued on 19 June 2015 in Germany in accordance with Part-FCL. The licence

listed the following type ratings: B777/787 as PIC, IR valid until 30 June 2021 and the

class rating for SEP(land)) and Touring Motor Glider (TMG).


4 December 2019. It listed the limitations TML; VNL; OML and SSL3. His class 1

medical certificate was valid until 9 December 2020.

Co-pilot

The 42-year-old co-pilot held an ATPL(A), initially issued on 24 April 2013 in Germa-

ny in accordance with Part-FCL. The licence listed the following type ratings:

B777/787 as COP, IR valid until 31 March 2021 and MD11 as COP, IR valid until

31 October 2020.

Her medical certificate pertaining to a Part-FCL licence was issued on

15 September 2020. Her class 1 medical certificate was valid until 6 October 2021.

Co-pilot

The 43-year-old co-pilot held an ATPL(A) initially issued on 22 November 2013 in

Germany in accordance with Part-FCL. The licence listed the type rating for

B777/787 as COP, IR valid until 30 November 2020.


11 August 2020. His class 1 medical certificate was valid until 20 September 2021.

Maintenance Personnel

The maintenance work to be performed during a ground time lasting several days in-

cluded tasks on the pitot-static system of the aircraft. The work to be performed was

described in job cards which were based on the Aircraft Maintenance Manual. These

job cards were divided into different tasks. Especially sensitive tasks included an in-

dependent inspection. Aircraft maintenance engineer A was charged with the perfor-

mance of the tasks. Aircraft maintenance engineer B was charged with the inde-

pendent inspection of the tasks aircraft maintenance engineer A was performing.

3 TML: Time Limitation, VNL: correction for defective near vision, OML: Valid only as or with qualified co-pilot, SSL: Special restriction as specified


- 6 -

Aircraft maintenance engineer A

According to the personnel records managed by the Luftfahrt-Bundesamt, the 40-

year-old engineer had completed his professional training as electronics technician

for aeronautical systems in January 2010. In June 2011, he received a licence for

certifying staff which listed the CAT A (valid for turbine aeroplanes) rating in accord-

ance with Regulation (EU) No. 2042/2003 Appendix III Part-66. At the time of the se-

rious incident, he held a licence for certifying staff issued in August 2018 listing the

CAT A and CAT B2 ratings. For category B2 the aircraft rating Boeing 747-400 (GE

CF6) was listed. The licence was valid until 7 August 2023.

Aircraft maintenance engineer B

According to the personnel records managed by the Luftfahrt-Bundesamt, the 33-

year-old engineer had completed his professional training as electronics technician

for aeronautical systems in January 2011. In February 2012, he received a licence

for certifying staff which listed the CAT A (valid for turbine aeroplanes) rating in ac-

cordance with Regulation (EU) No. 2042/2003 Appendix III Part-66. At the time of the

serious incident, he held a licence for certifying staff issued in September 2018 listing

the CAT A and CAT B2 ratings For category B2 the aircraft rating Boeing 777-

200/300 (GE 90) was listed. The licence was valid until 19 September 2023.

Aircraft Information

The Boeing 777F is a twin engine transport aircraft with a maximum take-off mass of

347,814 kg and a maximum landing mass of 260,815 kg. It is powered by 2 GE90-

110B1 jet engines.

The aircraft involved was manufactured in 2019, had the manufacturer’s serial num-

ber 66090, and had been listed in the German aircraft register since 28 March 2019.

According to the loadsheet, calculated take-off mass for the flight to Shanghai was

322,727 kg. Based on a fuel consumption of 76,055 kg for the flight to the arrival aer-

odrome, a landing mass of 246,672 kg was indicated. Centre of gravity was at 33.5%

Mean Aerodynamic Cord (MAC).

Pitot-Static System

The Boeing 777F fuselage is fitted with 3 Pitot tubes and 6 static ports for the pitot-

static system (Fig. 2).


- 7 -

The static ports are connected with the 6 Air Data Modules (ADM) and 2 Standby Air

Data Modules (SADM) via pneumatic lines (Fig. 3). These convert the pressures in

digital signals. Altitude and airspeed are calculated using these signals and then indi-

cated.

Fig. 2: Pitot-static system of the 777F, pitot probes and static ports Source: Boeing


- 8 -

The Static Air Data Modules (Static ADM) are located in the forward lower cargo

compartment (Fig. 4).

Fig. 3: Connections within the pitot-static system of the B777F Source: Operator


- 9 -

Meteorological Information

The aviation routine weather report (METAR) of 0920 hrs of Frankfurt/Main Airport

read:

Wind: 180° with 4 kt

Visibility: More than 10 km

Cloud: Few (1 to 2 octas) at 2,200 ft AGL

Temperature: 10°C

Dew-point: 8°C

QNH: 1,021 hPa

Trend: no significant change to be expected within the next 2 hours

With the take-off clearance a surface wind from 220° with 3 kt was given.

Fig. 4: Position of the Static ADMs/Static SADM at the forward lower cargo compartment Source: Boeing


- 10 -

The entire flight was conducted at daylight.

Aerodrome Information

Frankfurt Main Airport (EDDF) is located 6.5 NM south-west of Frankfurt City. Aero-

drome reference elevation is 364 ft AMSL. The airport was equipped with 4 paved

runways.

Take-off occurred on runway 25C. Landing occurred in the opposite direction on

runway 07C. On both sides a maximum area of 4,000 m length and 60 m width was

available for take-off and landing of the aircraft.

Flight Recorder

The operator made the FDR data available to the BFU. The BFU seized and ana-

lysed the CVR.

FDR:

Manufacturer: L3 Harris

Type: FA2100

Part Number (P/N): unknown

Serial Number (S/N): unknown

Recording duration: 71:55:44 h

CVR:

Manufacturer: L3 Harris

Type: FA2100

Part Number (P/N): FA2100-1025-22

Serial Number (S/N): 000931368

Recording duration: 02:04:14 hours

All recorded parameters were readable, the audio recording very understandable.

The CVR did not show any visible damage.


- 11 -

Wreckage and Impact Information

The examination of the airplane after the landing showed that the connecting lines of

the left and right static ports were not linked with the respective ADMs (Fig. 5).

The maintenance work taking place prior to the flight included opening the pneumatic

lines, flushing them with dry air and closing them again. The subsequent leak test

and system test were meant to ensure proper function of the pitot-static system. On

the respective job cards these tasks had been signed as performed and released.

One day later other personnel, not involved with the work already performed, con-

ducted a system test for altitude and airspeed of the Integrated Standby Flight Dis-

plays. According to the requirements only the center pitot-static system had to be

checked.

Fig. 5: Open connecting lines Source: Operator


- 12 -

Investigator in charge: Kostrzewa

Assistance: Bielfeldt, Blau, Buchwald, Kirchner, Schubert

Appendices

1. Graph of the relevant FDR data


- 13 -

Appendix 1: Graph of the relevant FDR data


- 14 -

This investigation is conducted in accordance with the regulation (EU) No. 996/2010 of the European Parliament and of the Council of 20 October 2010 on the investigation and prevention of accidents and incidents in civil aviation and the Federal German Law relating to the investigation of accidents and incidents associated with the operation of civil aircraft (Flugunfall-Untersuchungs-Gesetz - FlUUG) of 26 August 1998. The sole objective of the investigation is to prevent future accidents and incidents. The investigation does not seek to ascertain blame or apportion legal liability for any claims that may arise. This document is a translation of the German Investigation Report. Although every effort was made for the translation to be accurate, in the event of any discrepancies the original German document is the authentic version.

Published by: Bundesstelle für Flugunfalluntersuchung Hermann-Blenk-Str. 16 38108 Braunschweig Phone +49 531 35 48 - 0 Fax +49 531 35 48 - 246 Mail [email protected] Internet www.bfu-web.de

20-0887 Z1 EN V03

Documents

Transcript of 20-0887 Z1 EN V03